Troubleshooting and Fault Management

Last Updated: August 09, 2011

This chapter describes basic tasks that you can perform to troubleshoot your system and the network. For detailed troubleshooting procedures and scenarios, refer to the Internetwork Troubleshooting Guide . For complete details on all debug commands, refer to the Cisco IOS Debug Command Reference .

For a complete description of the troubleshooting commands in this chapter, refer to the “Troubleshooting and Fault Management Commands” chapter in “Cisco IOS System Management Commands” part of the Release 12.2 Cisco IOS Configuration Fundamentals Command Reference. To locate documentation of other commands that appear in this chapter, use the Cisco IOS Command Reference Master Index or search online.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Troubleshooting and Fault Management Task List

To manage network faults, you need to discover, isolate, and correct problems. You can discover problems with the system monitoring commands, isolate problems with the system test commands, and resolve problems with other commands, including debug commands.

To perform general fault management, perform the tasks described in the following sections:

In addition to the material presented in this chapter, many chapters in the Cisco IOS software configuration guides include fault management tasks specific to certain technologies and features. You can find these tasks in the “Monitoring and Maintaining” sections.

Displaying System Information Using show Commands

To provide information about system processes, the Cisco IOS software includes an extensive list of show EXEC commands. Following is a partial list of system management show commands. To display the information described, use the following commands in EXEC mode, as needed:

Command

Purpose

 
Router# show c2600

Displays information about the Cisco 2600 platform, including interrupts, IOS Priority Masks, and IDMA status, for troubleshooting.

 
Router# show c7200

Displays information about the CPU and midplane for the Cisco 7200 series routers.

 
Router# show context

Displays information stored in NVRAM when the router crashes. This command is only useful to your technical support representative. This command is supported on the Cisco 2600 and 7000 series routers.

 
Router# show controllers

Displays information specific to the hardware on a line card.

 
Router# show controllers logging

Displays logging information about a line card.

 
Router# show controllers tech-support

Displays general information about a line for use when reporting a problem.

 
Router# show controllers vip  slot-number  tech-support

Displays information about the Versatile Interface Processor (VIP) card for use when reporting a problem

 
Router# show diag

Displays hardware information (including DRAM and static RAM details) for line cards.

 
Router# show environment [all | last | table]

Displays a message indicating whether an environmental warning condition currently exists, the temperature and voltage information, the last measured value from each of the six test points stored in nonvolatile memory, or environmental specifications. Examples of systems that support this command include the Cisco 7000 and the Cisco 12000 series routers.

 
Router# show gsr

Displays hardware information on the Cisco 12000 series Gigabit Switch Router (GSR).

 
Router# show gt64010

Displays all GT64010 internal registers and interrupt status on the Cisco 7200 series routers.

 
Router# show memory [memory-type] [free] [summary]

Displays memory pool statistics including summary information about the activities of the system memory allocator and a block-by-block listing of memory use.

 
Router# show pci {hardware | bridge [register]}

Displays information about the peripheral component interconnect (PCI) hardware registers or bridge registers for the Cisco 2600 and 7000 series routers.

 
Router# show processes [cpu]

Displays information about all active processes.

 
Router# show processes memory

Displays information about memory usage.

 
Router# show protocols

Displays the configured protocols.

 
Router# show stacks

Displays stack usage of processes and interrupt routines, including the reason for the last system reboot. This command is only useful to your technical support representative.

 
Router# show subsys [class class | name name]

Displays subsystem information.

 
Router# show tcp [line-number]

Displays the status of TCP connections.

 
Router# show tcp brief [all]

Displays a concise description of TCP connection endpoints.

 
Router# show tdm connections [motherboard | slot  number]

Displays a snapshot of the time-division multiplexing (TDM) bus connection or data memory in a Cisco AS5200 access server.

 
Router# show tech-support [page] [password]

Displays information about the system for use when reporting a problem.

Refer to specific show commands in the tables of configuration commands found throughout the chapters in Cisco IOS software configuration guides. Refer to the Cisco IOS software command reference publications for detailed descriptions of the commands.

Testing Network Connectivity

Configuring the TCP Keepalive Packet Service

The TCP keepalive capability allows a router to detect when the host with which it is communicating experiences a system failure, even if data stops being sent (in either direction). This capability is most useful on incoming connections. For example, if a host failure occurs while the router is communicating with a printer, the router might never notice, because the printer does not generate any traffic in the opposite direction. If keepalives are enabled, they are sent once every minute on otherwise idle connections. If 5 minutes pass and no keepalives are detected, the connection is closed. The connection is also closed if the host replies to a keepalive packet with a reset packet. This will happen if the host crashes and comes back up again.

To generate the TCP keepalive packet service, use the following command in global configuration mode:

Command

Purposes

 
Router(config)# service {tcp-keepalives-in | tcp-keepalives-out}

Generates TCP keepalive packets on idle network connections, either incoming connections initiated by a remote host, or outgoing connections initiated by a user.

Testing Connections with the ping Command

As an aid to diagnosing basic network connectivity, many network protocols support an echo protocol. The protocol involves sending a special datagram to the destination host, then waiting for a reply datagram from that host. Results from this echo protocol can help in evaluating the path-to-host reliability, delays over the path, and whether the host can be reached or is functioning.

To invoke the echo protocol, use the following command in either user or privileged EXEC mode:

Command

Purposes

 
Router# ping [protocol] {host | address}

Invokes a diagnostic tool for testing connectivity.

Refer to specific ping commands in the tables of configuration commands found throughout the chapters in Cisco IOS software configuration guides. Refer to the Cisco IOS software command reference publications for detailed descriptions of the command.

Tracing Packet Routes

To trace the routes that packets will actually take when traveling to their destinations, use the following command in either user or privileged EXEC mode:

Command

Purposes

 
Router# trace [protocol] [destination]

Traces packet routes through the network (privileged level).

Logging System Messages

By default, routers send logging messages (including debug command output) a logging process. The logging process controls the distribution of logging messages to various destinations, such as the logging buffer, terminal lines, or a UNIX syslog server, depending on your configuration. The process also sends messages to the console. When the logging process is on, the messages are displayed on the console after the process that generated them has finished.

When the logging process is disabled, messages are sent only to the console. The messages are sent as they are generated, so error and debug output will be interspersed with prompts or output from the command.

You can set the severity level of the messages to control the type of messages displayed for the console and each destination. You can time-stamp log messages or set the syslog source address to enhance real-time debugging and management.

System logging messages are traditionally referred to as System Error Messages. Refer to the Cisco IOS Software System Error Messages publication for detailed information on specific system logging messages.

Enabling System Message Logging

System message logging is enabled by default. It must be enabled in order to send messages to any destination other than the console.

To disable message logging, use the no logging on command. Note that disabling the logging process can slow down the router because a process cannot continue until the messages are written to the console.

To reenable message logging after it has been disabled, use the following command in global configuration mode:

Command

Purposes

 
Router(config)# logging on

Enables message logging.

Enabling Message Logging for a Slave Card

To enable slave VIP cards to log status messages to the console (print the messages to the screen), use the following command in global configuration mode:

Command

Purposes

 
Router(config)# service slave-log

Enables slave message logging.

Setting the Syslog Destination

If message logging is enabled, you can send messages to specified locations, in addition to the console.

To set the locations that receive messages, use the following commands, as needed:

Command

Purposes

 
Router(config)# logging buffered [size]

Logs messages to an internal buffer.

 
Router(config)# logging  host

Logs messages to a syslog server host.

 
Router# terminal monitor

Logs messages to a nonconsole terminal.

The logging buffered command copies logging messages to an internal buffer. The buffer is circular, so newer messages overwrite older messages after the buffer is full. To display the messages that are logged in the buffer, use the show logging EXEC command. The first message displayed is the oldest message in the buffer. To clear the current contents of the buffer, use the clear logging privileged EXEC command.

The loggingcommand identifies a syslog server host to receive logging messages. The host argument is the name or IP address of the host. By issuing this command more than once, you build a list of syslog servers that receive logging messages. The no loggingcommand deletes the syslog server with the specified address from the list of syslogs.

The terminal monitor EXEC command locally accomplishes the task of displaying the system logging messages to a terminal.

Configuring Synchronization of Logging Messages

You can configure the system to synchronize unsolicited messages and debug command output with solicited device output and prompts for a specific line. You can identify the types of messages to be output asynchronously based on the level of severity. You can also determine the maximum number of buffers for storing asynchronous messages for the terminal after which messages are dropped.

When synchronous logging of unsolicited messages and debug command output is turned on, unsolicited device output is displayed on the console or printed after solicited device output is displayed or printed. Unsolicited messages and debug command output is displayed on the console after the prompt for user input is returned. Therefore, unsolicited messages and debug command output are not interspersed with solicited device output and prompts. After the unsolicited messages are displayed, the console displays the user prompt again.

To configure for synchronous logging of unsolicited messages and debug command output with solicited device output and prompts, use the following commands beginning in global configuration mode:

SUMMARY STEPS

1.    Router(config)# line [aux| console | vty] beginning-line-number [ending-line-number]

2.    Router(config-line)# logging synchronous [level severity-level | all] [limit number-of-buffers]


DETAILED STEPS
  Command or Action Purpose
Step 1
Router(config)# line [aux| console | vty] beginning-line-number [ending-line-number] 

Specifies the line to be configured for synchronous logging of messages.

 
Step 2
Router(config-line)# logging synchronous [level severity-level | all] [limit number-of-buffers]  

Enables synchronous logging of messages.

 

Enabling Time-Stamps on Log Messages

By default, log messages are not time-stamped. To enable time-stamping of log messages, use either of the following commands in global configuration mode:

Command

Purposes

 
Router(config)# service timestamps log uptime
 
 or
 
Router(config)# service timestamps log datetime [msec] [localtime] [show-timezone]
 		 
           
 Enables log time stamps.
 		 
         
 
         
       
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Limiting the Error Message Severity Level and Facilities
 
     
 
      
 
        
         
       
 You can limit the number of messages displayed to the selected device by specifying the severity level of the error message (see the table below for level descriptions). To do so, use the following commands in global configuration mode, as needed: 
 
       
 
         
          
        
 
          
          
 
            
 Command 
 		 
            
 Purposes 
 		 
          
 
          
          
          
 
            
Router(config)# logging console  level
 		 
            
 Limits the number of messages logged to the console. 
 		 
          
 
          
 
            
Router(config)# logging monitor  level
 		 
            
 Limits the number of messages logged to the terminal lines. 
 		 
          
 
          
 
            
Router(config)# logging trap  level
 		 
            
 Limits the number of messages logged to the syslog servers. 
 		 
          
 
          
        
 
       
 
       
 If you have enabled syslog messages traps to be sent to a Simple Network Management Protocol (SNMP) network management station with the snmp-server enable trapcommand, you can change the level of messages sent and stored in a history table on the router. You can also change the number of messages that get stored in the history table. 
 
       
 Messages are stored in the history table because SNMP traps are not guaranteed to reach their destination. By default, one message of the level warning and above (see the table above) is stored in the history table even if syslog traps are not enabled. 
 
       
 To change level and table size defaults, use the following commands in global configuration mode: 
 
      
 
       
        
      SUMMARY STEPS 
      
 
        1.    Router(config)# logging history level 
 
      
 
        2.    Router(config)# logging history size number 
 
      
 
      DETAILED STEPS 
       
        
       
        
      
 
        
        
 
           
         Command or Action 
         Purpose 
        
 
        
 
          
          
 
           Step 1 
          
 
          
          
 
            Router(config)# logging history level   
          
 
          
 Changes the default level of syslog messages stored in the history file and sent to the SNMP server. 
  		 
        
 
        
 
          
          
 
           Step 2 
          
 
          
          
 
            Router(config)# logging history size number   
          
 
          
 Changes the number of syslog messages that can be stored in the history table. 
  		 
        
 
        
      
 
      What to Do Next 
      
 
 
       
        
      
 
        
        
 
         
Note		 
         
 
          
 The table below lists the level keywords and severity level. For SNMP usage, the severity level values use +1. For example, emergency equals 1 not 0 and critical equals 3 not 2. 
          
 
        
 
        
      
 
      
 The logging console command limits the logging messages displayed on the console terminal to messages with a level number at or below the specified severity level, which is specified by the level argument. The table below lists the error message level keywords and corresponding UNIX syslog definitions in order from the most severe level to the least severe level. 
 
      
 
        
         
       
 
         
         
 
          Table 1 
          System Logging Message Severity Levels  
         
 
         
       
 
       
 
         
         
 
           
 Level Keyword 
 		 
           
 Level 
 		 
           
 Description 
 		 
           
 Syslog Definition 
 		 
         
 
         
         
         
 
           
  emergencies  
 		 
           
 0 
 		 
           
 System unusable 
 		 
           
 LOG_EMERG 
 		 
         
 
         
 
           
  alerts  
 		 
           
  1  
 		 
           
 Immediate action needed 
 		 
           
 LOG_ALERT 
 		 
         
 
         
 
           
  critical  
 		 
           
  2  
 		 
           
 Critical conditions 
 		 
           
 LOG_CRIT 
 		 
         
 
         
 
           
  errors  
 		 
           
  3  
 		 
           
 Error conditions 
 		 
           
 LOG_ERR 
 		 
         
 
         
 
           
  warnings  
 		 
           
 4 
 		 
           
 Warning conditions 
 		 
           
 LOG_WARNING 
 		 
         
 
         
 
           
  notifications  
 		 
           
  5  
 		 
           
 Normal but significant condition 
 		 
           
 LOG_NOTICE 
 		 
         
 
         
 
           
  informational  
 		 
           
  6  
 		 
           
 Informational messages only 
 		 
           
 LOG_INFO 
 		 
         
 
         
 
           
  debugging  
 		 
           
 7 
 		 
           
 Debugging messages 
 		 
           
 LOG_DEBUG 
 		 
         
 
         
       
 
      
 
      
 The no logging console command disables logging to the console terminal. 
 
      
 The default is to log messages to the console at the debugging level and those level numbers that are lower, which means all levels. The logging monitor command defaults to debugging also. The logging trap command defaults to the informational level. 
 
      
 To display logging messages on a terminal, use the terminal monitor EXEC command. 
 
      
 Current software generates the following four categories of error messages: 
 
       
        
      
     
       
  •  
          Error messages about software or hardware malfunctions, displayed at levels warnings through emergencies 
    •  
       
  •  
          Output from the debug commands, displayed at the debugging level 
    •  
       
  •  
          Interface up/down transitions and system restart messages, displayed at the notifications level 
    •  
       
  •  
          Reload requests and low-process stack messages, displayed at the informational level 
    •  
      
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Defining the UNIX System Logging Facility
 
     
 
      
 You can log messages produced by UNIX system utilities. To do this, enable this type logging and define the UNIX system facility from which you want to log messages. The table below lists the UNIX system facilities supported by the Cisco IOS software. Consult the operator manual for your UNIX operating system for more information about these UNIX system facilities. The syslog format is compatible with Berkeley Standard Distribution (BSD) UNIX version 4.3. 
 
      
 To define UNIX system facility message logging, use the following command in global configuration mode: 
 
      
 
        
         
       
 
         
         
 
           
 Command 
 		 
           
 Purposes 
 		 
         
 
         
         
         
 
           
Router(config)# logging facility  facility-type
 		 
           
 Configures system log facilities. 
 		 
         
 
         
       
 
      
 
      
 
        
         
       
 
         
         
 
          Table 2 
          Logging Facility Type Keywords  
         
 
         
       
 
       
 
         
         
 
           
 Facility Type Keyword 
 		 
           
 Description 
 		 
         
 
         
         
         
 
           
  auth  
 		 
           
 Indicates the authorization system. 
 		 
         
 
         
 
           
  cron  
 		 
           
 Indicates the cron facility. 
 		 
         
 
         
 
           
  daemon  
 		 
           
 Indicates the system daemon. 
 		 
         
 
         
 
           
  kern  
 		 
           
 Indicates the Kernel. 
 		 
         
 
         
 
           
  local0-7  
 		 
           
 Reserved for locally defined messages. 
 		 
         
 
         
 
           
  lpr  
 		 
           
 Indicates line printer system. 
 		 
         
 
         
 
           
  mail  
 		 
           
 Indicates mail system. 
 		 
         
 
         
 
           
  news  
 		 
           
 Indicates USENET news. 
 		 
         
 
         
 
           
  sys9  
 		 
           
 Indicates system use. 
 		 
         
 
         
 
           
  sys10  
 		 
           
 Indicates system use. 
 		 
         
 
         
 
           
  sys11  
 		 
           
 Indicates system use. 
 		 
         
 
         
 
           
  sys12  
 		 
           
 Indicates system use. 
 		 
         
 
         
 
           
  sys13  
 		 
           
 Indicates system use. 
 		 
         
 
         
 
           
  sys14  
 		 
           
 Indicates system use. 
 		 
         
 
         
 
           
  syslog  
 		 
           
 Indicates the system log. 
 		 
         
 
         
 
           
  user  
 		 
           
 Indicates user process. 
 		 
         
 
         
 
           
  uucp  
 		 
           
 Indicates UNIX-to-UNIX copy system. 
 		 
         
 
         
       
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Displaying Logging Information
 
     
 
      
 To display logging information, use the following commands in EXEC mode, as needed:
 
      
 
        
         
       
 
         
         
 
           
 Command
 		 
           
 Purposes
 		 
         
 
         
         
         
 
           
Router# show logging
 		 
           
 Displays the state of syslog error and event logging, including host addresses, whether console logging is enabled, and other logging statistics.
 		 
         
 
         
 
           
Router# show controllers vip  slot-number logging
 		 
           
 Displays the state of syslog error and event logging of a VIP card, including host addresses, whether console logging is enabled, and other logging statistics.
 		 
         
 
         
 
           
Router# show logging history 
 		 
           
 Displays information in the syslog history table such as the table size, the status of messages, and the text of the messages stored in the table.
 		 
         
 
         
       
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Logging Errors to a UNIX Syslog Daemon
 
     
 
      
 To configure the syslog daemon on a 4.3 BSD UNIX system, include a line such as the following in the /etc/syslog.conf file:
 
      
local7.debugging /usr/adm/logs/cisco.log

 
      
 The debugging keyword specifies the syslog level; see Logging Errors to a UNIX Syslog Daemon for a general description of other keywords. The local7 keyword specifies the logging facility to be used; see Logging Errors to a UNIX Syslog Daemon for a general description of other keywords.
 
      
 The syslog daemon sends messages at this level or at a more severe level to the file specified in the next field. The file must already exist, and the syslog daemon must have permission to write to it.
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Setting the Syslog Source Address
 
     
 
      
 By default, a syslog message contains the IP address of the interface it uses to leave the router. To set all syslog messages to contain the same IP address, regardless of which interface they use, use the following command in global configuration mode.
 
      
 
        
         
       
 
         
         
 
           
 Command
 		 
           
 Purposes
 		 
         
 
         
         
         
 
           
Router(config)# logging source-interface type number

 		 
           
 Sets the syslog source address.
 		 
         
 
         
       
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
   
 
   
 
     
      
    
Using Field Diagnostics on Line Cards
 
    
 
     
 Each line card on the Cisco 12000 series routers can perform field diagnostic testing to isolate faulty hardware without disrupting normal operation of the system. However, performing field diagnostic testing on a line card does halt all activity on the line card for the duration of the testing. After successful completion of the field diagnostic testing, the Cisco IOS software is automatically reloaded on the line card.
 
      
       
     
 
       
       
 
        
Note		 
        
 
         
 The field diagnostic diag command must be executed from the Gigabit Route Processor (GRP) main console port. 
         
 
       
 
       
     
 
     
 To perform field diagnostic testing on a line card, use the following command in privileged EXEC mode:
 
     
 
       
        
      
 
        
        
 
          
 Command
 		 
          
 Purposes
 		 
        
 
        
        
        
 
          
Router# diag  slot-number [previous | post | verbose | wait]
 		 
          
 Specifies the line card on which you want to perform diagnostic testing. 
 
 Optionally, specifies that previous test results are displayed, that only extended power-on self-tests (POST) be performed, that the maximum messages are displayed, or that the Cisco IOS software not be reloaded on the line card after successful completion of the tests. The following prompt is displayed:
 
Running Diags will halt ALL activity on the requested slot. [confirm]

 
 At the prompt, press Return to confirm that you want to perform field diagnostic testing on the specified line card, or type no to stop the testing.
 		 
        
 
        
      
 
     
 
     
 To stop field diagnostic testing on a line card, use either of the following commands in privileged EXEC mode:
 
     
 
       
        
      
 
        
        
 
          
 Command
 		 
          
 Purpose
 		 
        
 
        
        
        
 
          
Router# diag  slot-number  halt
 
 
 or
 
Router# no diag  slot-number 
 		 
          
 Specifies the line card on which you want to stop diagnostic testing. 
 		 
        
 
        
      
 
     
 
      
       
     
 
       
       
 
        
Note		 
        
 
         
 When you stop the field diagnostic test, the line card remains down (that is, in an unbooted state). In most cases, you stopped the testing because you need to remove the line card or replace the line card. If that is not the case and you want to bring the line card back up (that is, online), you must use the microcode reload global configuration command or power cycle the line card. 
         
 
       
 
       
     
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
Troubleshooting Specific Line Cards
 
    
 
     
 Cisco IOS provides the execute-on command to allow you to issue Cisco IOS commands (such as show commands) to a specific line card for monitoring and maintenance. For example, you could show which Cisco IOS image is loaded on the card in slot 3 of a Cisco 12012 Gigabit Switch Router (GSR) by issuing the execute-on slot 3 show versioncommand. You can also use this command for troubleshooting cards in the dial shelf of Cisco access servers.
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
Storing Line Card Crash Information
 
    
 
     
 This section explains how to enable storing of crash information for a line card and optionally specify the type and amount of information stored. Technical support representatives need to be able to look at the crash information from the line card to troubleshoot serious problems on the line card. The crash information contains all the line card memory information, including the main memory and transmit and receive buffer information. 
 
      
       
     
 
       
       
 
        
Caution		 
        
 
         
 
 Use the exception linecard global configuration command only when directed by a technical support representative, and only enable options that the technical support representative requests you to enable.
 
         
 
       
 
       
     
 
     
 To enable and configure the crash information options for a line card, use the following command in global configuration mode.
 
     
 
       
        
      
 
        
        
 
          
 Command
 		 
          
 Purpose
 		 
        
 
        
        
        
 
          
Router(config)# exception linecard {all | slot  slot-number} [corefile filename | main-memory size [k | m] | queue-ram size [k | m] | rx-buffer  size [k | m] | sqe-register-rx | sqe-register-tx | tx-buffer size [k | m]]
 		 
          
 Specifies the line card for which you want crash information when a line card resets. Optionally, specify the type and amount of memory to be stored. 
 		 
        
 
        
      
 
     
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
Creating Core Dumps for System Exceptions
 
    
 
     
 “System exceptions” are any unexpected system shutdowns or reboots (most frequently caused by a system failure, commonly referred to as a “system crash”). When an exception occurs, it is sometimes useful to obtain a full copy of the memory image (called a core dump) to identify the cause of the unexpected shutdown. Not all exception types will produce a core dump. 
 
     
 Core dumps are generally useful only to your technical support representative. The core dump file, which is a very large binary file, can be transferred to a Trivial File Transfer Protocol (TFTP), File Transfer Protocol (FTP), or Remote Copy Protocol (RCP) server, or (on limited platforms) saved to the flash disk, and subsequently interpreted by technical personnel who have access to source code and detailed memory maps. 
 
      
       
     
 
       
       
 
        
Caution		 
        
 
         
 
 Use the exception commands only under the direction of a technical support representative. Creating a core dump while the router is functioning in a network can disrupt network operation. 
 
         
 
       
 
       
     
 
    
 
    
 
      
     
 
     
 
    
 
    
 
      
       
     
Specifying the Destination for the Core Dump File
 
     
 
      
 To configure the router to generate a core dump, you must enable exception dumps and configure a destination for the core dump file, as described in the following sections: 
 
     
 
     
 
       
      
 
      
 
     
 
     
 
       
        
      
Using TFTP for Core Dumps
 
      
 
       
 
         
          
        
 Due to a limitation of most TFTP applications, the router will dump only the first 16 MB of the core file. Therefore, if your router’s main memory is larger than 16 MB, do not use TFTP. 
 
        
 To configure a router for a core dump using TFTP, use the following commands in global configuration mode:
 
       
 
        
         
       SUMMARY STEPS 
       
1.     exception protocol tftp  
 
       
2.     exception dump   ip-address  
 
       
3.     exception core-file  [filepath/]filename
 
       
 
       DETAILED STEPS 
       
 
         
         
 
            
          Command or Action 
          Purpose 
         
 
         
 
           
           
 
            Step 1 
           
 
           
           
 
              exception protocol tftp   
            
 
            
 
            
 
            Example: 
            
 
   
           
 
           
 (Optional) Explicitly specifies TFTP as the protocol to be used for router exceptions (core dumps for unexpected system shutdowns).
  
             
           
 
             
             
 
              Note    
               Because TFTP is the default exception protocol, the exception protocol tftp command does not need to be used unless the protocol has been previously changed to ftp or rcp in your system’s configuration. To determine if the exception protocol has been changed, use the show running-config command in EXEC mode. 
             
 
             
           
  		 
         
 
         
 
           
           
 
            Step 2 
           
 
           
           
 
              exception dump   ip-address   
            
 
            
 
            
 
            Example: 
            
 
   
           
 
           
 Configures the router to dump a core file to the specified server if the router crashes. 
  		 
         
 
         
 
           
           
 
            Step 3 
           
 
           
           
 
              exception core-file  [filepath/]filename 
            
 
            
 
            
 
            Example: 
            
 
   
           
 
           
 (Optional) Specifies the name to be used for the core dump file. The file usually must pre-exist on the TFTP server, and be writable. 
  		 
         
 
         
       
 
       What to Do Next 
       
 
 
       
 For example, the following command configures a router to send a core file to the server at the IP address 172.17.92.2. As the exception protocol is not specified, the default protocol of TFTP will be used.
 
       
Router(config)# exception dump 172.17.92.2

 
       
 The core dump is written to a file named "hostname -core" on the TFTP server, where hostname is the name of the route (in the example above, the file would be named Router-core). You can change the name of the core file by adding the exception core-file filename configuration command. 
 
       
 Depending on the TFTP server application used, it may be necessary to create, on the TFTP server, the empty target file to which the router can write the core. Also, make sure there is enough memory on your TFTP server to hold the complete core dump. 
 
       
 
      
 
      
 
       
 
       
 
      
 
     
 
     
 
       
        
      
Using FTP for Core Dumps
 
      
 
       
 
         
          
        
 To configure the router for a core dump using FTP, use the following commands in global configuration mode:
 
       
 
        
         
       SUMMARY STEPS 
       
1.    Router(config)# ip ftp username username
 
       
2.    Router(config)# ip ftp password[type] password
 
       
3.    Router(config)# exception protocol ftp
 
       
4.    Router(config)# exception dump ip-address
 
       
5.    Router(config)# exception core-file filename
 
       
 
       DETAILED STEPS 
       
 
         
         
 
            
          Command or Action 
          Purpose 
         
 
         
 
           
           
 
            Step 1 
           
 
           
           
 
             Router(config)# ip ftp username username  
           
 
           
 (Optional) Configures the user name for FTP connections.
  		 
         
 
         
 
           
           
 
            Step 2 
           
 
           
           
 
             Router(config)# ip ftp password[type] password  
           
 
           
 (Optional) Specifies the password to be used for FTP connections.
  		 
         
 
         
 
           
           
 
            Step 3 
           
 
           
           
 
             Router(config)# exception protocol ftp  
           
 
           
 Specifies that FTP should be used for core dump file transfers.
  		 
         
 
         
 
           
           
 
            Step 4 
           
 
           
           
 
             Router(config)# exception dump ip-address  
           
 
           
 Configures the router to dump a core file to a particular server if the router crashes.
  		 
         
 
         
 
           
           
 
            Step 5 
           
 
           
           
 
             Router(config)# exception core-file filename  
           
 
           
 (Optional) Specifies the name to be used for the core dump file. 
  		 
         
 
         
       
 
       What to Do Next 
       
 
 
       
 The following example configures a router to use FTP to dump a core file named “dumpfile” to the FTP server at 172.17.92.2 when it crashes.
 
       
ip ftp username red
ip ftp password blue
exception protocol ftp
exception dump 172.17.92.2
exception core-file dumpfile
 
       
 
      
 
      
 
       
 
       
 
      
 
     
 
     
 
       
        
      
Using rcp for Core Dumps
 
      
 
       
 
         
          
        
 The remote copy protocol can also be used to send a core dump file. To configure the router to send core dump files using rcp, use the following commands:
 
       
 
        
         
       SUMMARY STEPS 
       
1.    ip rcmd remote-username username
 
       
2.     exception protocol rcp  
 
       
3.     exception dump   ip-address  
 
       
4.     exception core-file   filename  
 
       
 
       DETAILED STEPS 
       
 
         
         
 
            
          Command or Action 
          Purpose 
         
 
         
 
           
           
 
            Step 1 
           
 
           
           
 
             ip rcmd remote-username username  
           
 
           
 (Optional) Specifies the username sent by the router to the remote server with an rcp copy/write request. The remote rcp server must configured to grant write access to the specified username (in other words, an account must be defined on the network server for the username). 
  		 
         
 
         
 
           
           
 
            Step 2 
           
 
           
           
 
              exception protocol rcp   
            
  
           
 
           
 Configures the rcp as the protocol to use for sending core dump files. 
  		 
         
 
         
 
           
           
 
            Step 3 
           
 
           
           
 
              exception dump   ip-address   
            
 
            
 
            
 
            Example: 
            
 
   
           
 
           
 Configures the router to dump a core file to the specified server if the router crashes. 
  		 
         
 
         
 
           
           
 
            Step 4 
           
 
           
           
 
              exception core-file   filename   
            
 
            
 
            
 
            Example: 
            
 
   
           
 
           
 (Optional) Specifies the name to be used for the core dump file.
  		 
         
 
         
       
 
       What to Do Next 
       
 
 
       
 When an rcp username is not configured through the ip rcmd remote-username command, the rcp username defaults to the username associated with the current terminal (tty) connection. For example, if the user is connected to the router through Telnet and was authenticated through the username command, the router software sends the Telnet username as the rcp username. If the terminal username is not available, the router hostname will be used as the rcp username. 
 
       
 
      
 
      
 
       
 
       
 
      
 
     
 
     
 
       
        
      
Using a Flash Disk for Core Dumps
 
      
 
       
 Some router platforms support the Flash disk as an alternative to the linear Flash memory or PCMCIA Flash card. The large storage capacity of these Flash disks makes them good candidates for another means of capturing a core dump. To configure a router for a core dump using a Flash disk, use the following command in global configuration mode:
 
       
 
         
          
        
 
          
          
 
            
 Command
 		 
            
 Purpose
 		 
          
 
          
          
          
 
            
Router(config)# exception flash
 [procmem
 |iomem
 | all
] 
device-name
[:
partition-number
] [erase
 | no_erase
]
 		 
            
 Configures the router for a core dump using a flash disk.
 		 
          
 
          
 
            
Router(config)# exception core-file filename 
 
 		 
            
 (Optional) Specifies the name to be used for the core dump file.
 		 
          
 
          
        
 
       
 
       
 The show flash all EXEC command will list the devices you can use for the exception flash command. 
 
      
 
      
 
       
 
       
 
      
 
     
 
    
 
    
 
      
       
     
Creating an Exception Memory Core Dump
 
     
 
      
 To cause the router to create a core dump and reboot when certain memory size parameters are violated during the debugging process, use the following commands in global configuration mode:
 
      
 As a debugging procedure, you can cause the router to create a core dump and reboot when certain memory size parameters are violated. The following exception memory commands are used to trigger a core dump:
 
      
 
        
         
       
 
         
         
 
           
 Command
 		 
           
 Purpose
 		 
         
 
         
         
         
 
           
Router(config)# exception memory minimum bytes 
 		 
           
 Triggers a core dump and system reload when the amount of free memory falls below the specified number of bytes. 
  
             
           
     
            
  •  Do not specify too low a memory value, as the router needs some amount of free memory to provide the core dump.
    •  
            
  •  If you enter a size that is greater than the free memory (and the exception dump command has been configured), a core dump and router reload is generated after 60 seconds.
    •  
           
 		 
         
 
         
 
           
Router(config)# memory check-interval seconds 
 		 
           
 (Optional) Increases the interval at which memory will be checked. The default is 60 seconds, but much can happen in 60 seconds to mask the cause of corruption. Reducing the interval will increase CPU utilization (by around 12%) which will be acceptable in most cases, but will also increase the chance of getting a usable core. To make sure CPU utilization doesn't hit 100%, you should gradually decrease the interval on busy routers. The ideal interval is as low as possible without causing other system problems.
 		 
         
 
         
 
           
Router(config)# exception memory fragment bytes 
 		 
           
 Triggers a core dump and system reload when the amount of contiguous (non-fragmented) free memory falls below the specified number of bytes. 
 		 
         
 
         
 
           
Router(config)# exception core-file filename 
 
 		 
           
 (Optional) Specifies the name to be used for the core dump file. The file usually must exist on the TFTP server, and be writable. Note that the file will be the same size as the amount of processor memory on the router.
 		 
         
 
         
       
 
      
 
      
 Note that the exception memory minimum command is primarily useful if you anticipate running out of memory before a core dump can be triggered or other debugging can be performed (rapid memory leak); if the memory leak is gradual (slow drift), you have generally have time to perform debugging before the system runs out of memory and must be reloaded.
 
      
 By default, the number of free memory bytes is checked every 60 seconds when these commands are configured. The frequency of this checking can be increased using the memory check-interval seconds command. 
 
      
 The exception dump ip-addresscommand must be configured with these commands. If the exception dump command is not configured, the router reloads without triggering a core dump. 
 
      
 The following example configures the router to monitor the free memory. If the memory falls below 250000 bytes, the core dump is created and the router reloads.
 
      
exception dump 172.18.92.2
exception core-file memory.overrun
exception memory minimum 250000
 
     
 
     
 
       
      
 
      
 
     
 
     
 
       
        
      
Setting a Spurious Interrupt Core Dump
 
      
 
       
 During the debugging process, you can configure the router to create a spurious interrupt core dump and reboot when a specified number of interrupts have occurred.
 
        
         
       
 
         
         
 
          
Caution		 
          
 
           
 
 Use the exception spurious-interrupt global configuration command only when directed by a technical support representative and only enable options requested by the technical support representative.
 
           
 
         
 
         
       
 
       
 To enable and configure the crash information for spurious interrupts, use the following commands in global configuration mode:
 
       
 
         
          
        
 
          
          
 
            
 Command
 		 
            
 Purpose
 		 
          
 
          
          
          
 
            
Router(config)# exception spurious-interrupt number
 		 
            
 Sets the maximum number of spurious interrupts to include in the core dump before reloading.
 		 
          
 
          
 
            
Router(config)# exception dump ip-address 
 
 
 or
 
Router(config)# exception flash 
 		 
            
 Specifies the destination for the core dump file. 
 		 
          
 
          
        
 
       
 
       
 The following example configures a router to create a core dump with a limit of two spurious interrupts:
 
       
exception spurious-interrupt 2 
exception dump 209.165.200.225 
 
      
 
      
 
       
 
       
 
      
 
     
 
    
 
   
 
   
 
     
      
    
Enabling Debug Operations
 
    
 
     
 Your router includes hardware and software to aid in troubleshooting internal problems and problems with other hosts on the network. The debug privileged EXEC mode commands start the console display of several classes of network events. The following commands describe in general the system debug message feature. Refer to the Cisco IOS Debug Command Reference for all information regarding debug commands. Also refer to the Internetwork Troubleshooting Guide  publication for additional information.
 
     
 To enable debugging operations, use the following commands:
 
     
 
       
        
      
 
        
        
 
          
 Command
 		 
          
 Purposes
 		 
        
 
        
        
        
 
          
Router# show debugging 
 		 
          
 Displays the state of each debugging option.
 		 
        
 
        
 
          
Router# debug ?
 		 
          
 Displays a list and brief description of all the debug command options.
 		 
        
 
        
 
          
Router# debug  command
 		 
          
 Begins message logging for the specified debug command.
 		 
        
 
        
 
          
Router# no debug  command
 		 
          
 Turns message logging off for the specified debug command.
 		 
        
 
        
      
 
     
 
      
       
     
 
       
       
 
        
Caution		 
        
 
         
 
 The system gives high priority to debugging output. For this reason, debugging commands should be turned on only for troubleshooting specific problems or during troubleshooting sessions with technical support personnel. Excessive debugging output can render the system inoperable.
 
         
 
       
 
       
     
 
     
 You can configure time-stamping of system debug messages. Time-stamping enhances real-time debugging by providing the relative timing of logged events. This information is especially useful when customers send debugging output to your technical support personnel for assistance. To enable time-stamping of system debug messages, use either of the following commands in global configuration mode:
 
     
 
       
        
      
 
        
        
 
          
 Command
 		 
          
 Purposes
 		 
        
 
        
        
        
 
          
Router(config)# service timestamps debug uptime
 
 
 or
 
Router(config)# service timestamps debug datetime [msec] [localtime] [show-timezone]
 		 
          
 Enables time-stamping of system debug messages.
 		 
        
 
        
      
 
     
 
     
 Normally, the messages are displayed only on the console terminal. Refer to the section “Setting the Syslog Destination” earlier in this chapter to change the output device. 
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
Enabling Conditionally Triggered Debugging
 
    
 
     
 When the Conditionally Triggered Debugging feature is enabled, the router generates debugging messages for packets entering or leaving the router on a specified interface; the router will not generate debugging output for packets entering or leaving through a different interface. You can specify the interfaces explicitly. For example, you may only want to see debugging messages for one interface or subinterface. You can also turn on debugging for all interfaces that meet specified condition. This feature is useful on dial access servers, which have a large number of ports. 
 
     
 Normally, the router will generate debugging messages for every interface, resulting in a large number of messages. The large number of messages consumes system resources, and can affect your ability to find the specific information you need. By limiting the number of debugging messages, you can receive messages related to only the ports you wish to troubleshoot.
 
     
 Conditionally Triggered Debugging controls the output from the following protocol-specific debug commands:
 
      
       
     
     
      
  •   debug aaa  {accounting | authorization | authentication}
    •  
      
  •   debug dialer  {events | packets}
    •  
      
  •   debug isdn  {q921 | q931}
    •  
      
  •   debug modem  {oob | trace}
    •  
      
  •   debug ppp {all | authentication | chap | error | negotiation | multilink events | packet}
    •  
     
 
     
 Although this feature limits the output of the commands listed, it does not automatically enable the generation of debugging output from these commands. Debugging messages are generated only when the protocol-specific debug command is enabled. The debug command output is controlled through two processes:
 
      
       
     
     
      
  •  The protocol-specific debug commands specify which protocols are being debugged. For example, the debug dialer events command generates debugging output related to dialer events. 
    •  
      
  •  The debug condition commands limit these debugging messages to those related to a particular interface. For example, the debug condition username bob command generates debugging output only for interfaces with packets that specify a username of bob.
    •  
     
 
     
 To configure Conditionally Triggered Debugging, perform the tasks described in the following sections:
 
    
 
    
 
      
     
 
     
 
    
 
    
 
      
       
     
Enabling Protocol-Specific debug Commands
 
     
 
      
 In order to generate any debugging output, the protocol-specific debug command for the desired output must be enabled. Use the show debugging command to determine which types of debugging are enabled. To display the current debug conditions, use the show debug condition command. To enable the desired protocol-specific debug commands, use the following commands in privileged EXEC mode:
 
      
 
        
         
       
 
         
         
 
           
 Command
 		 
           
 Purpose
 		 
         
 
         
         
         
 
           
Router# show debugging
 		 
           
 Determines which types of debugging are enabled.
 		 
         
 
         
 
           
Router# show debug condition [condition-id]
 		 
           
 Displays the current debug conditions.
 		 
         
 
         
 
           
Router# debug protocol
 		 
           
 Enables the desired debugging commands.
 		 
         
 
         
 
           
Router# no debug  protocol
 		 
           
 Disables the debugging commands that are not desired.
 		 
         
 
         
       
 
      
 
      
 If you do not want output, disable all the protocol-specific debug commands.
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Enabling Conditional Debugging Commands
 
     
 
      
 If no debug condition commands are enabled, all debugging output, regardless of the interface, will be displayed for the enabled protocol-specific debug commands.
 
      
 The first debug condition command you enter enables conditional debugging. The router will display only messages for interfaces that meet one of the specified conditions. If multiple conditions are specified, the interface must meet at least one of the conditions in order for messages to be displayed.
 
      
 To enable messages for interfaces specified explicitly or for interfaces that meet certain conditions, perform the tasks described in the following sections:
 
     
 
     
 
       
      
 
      
 
     
 
     
 
       
        
      
Displaying Messages for One Interface
 
      
 
       
 To disable debugging messages for all interfaces except one, use the following command in privileged EXEC mode:
 
       
 
         
          
        
 
          
          
 
            
 Command
 		 
            
 Purpose
 		 
          
 
          
          
          
 
            
Router# debug condition interface  interface
 		 
            
 Enables debugging output for only the specified interface.
 		 
          
 
          
        
 
       
 
       
 To reenable debugging output for all interfaces, use the no debug interfacecommand. 
 
      
 
      
 
       
 
       
 
      
 
     
 
     
 
       
        
      
Displaying Messages for Multiple Interfaces
 
      
 
       
 
         
          
        
 To enable debugging messages for multiple interfaces, use the following commands in privileged EXEC mode:
 
       
 
        
         
       SUMMARY STEPS 
       
1.    Router# debug condition interface  interface
 
       
2.    Router# debug condition interface  interface
 
       
 
       DETAILED STEPS 
       
 
         
         
 
            
          Command or Action 
          Purpose 
         
 
         
 
           
           
 
            Step 1 
           
 
           
           
 
             Router# debug condition interface  interface  
           
 
           
 Enables debugging output for only the specified interface
  		 
         
 
         
 
           
           
 
            Step 2 
           
 
           
           
 
             Router# debug condition interface  interface  
           
 
           
 Enable debugging messages for additional interfaces. Repeat this task until debugging messages are enabled for all desired interfaces.
  		 
         
 
         
       
 
       What to Do Next 
       
 
 
       
 If you specify more than one interface by entering this command multiple times, debugging output will be displayed for all of the specified interfaces. To turn off debugging on a particular interface, use the no debug interface command. If you use the no debug interface all command or remove the last debug interface command, debugging output will be reenabled for all interfaces.
 
       
 
      
 
      
 
       
 
       
 
      
 
     
 
     
 
       
        
      
Limiting the Number of Messages Based on Conditions
 
      
 
       
 The router can monitor interfaces to learn if any packets contain the specified value for one of the following conditions:
 
        
         
       
     
        
  •  username
    •  
        
  •  calling party number
    •  
        
  •  called party number
    •  
       
 
       
 If you enter a condition, such as calling number, debug output will be stopped for all interfaces. The router will then monitor every interface to learn if a packet with the specified calling party number is sent or received on any interfaces. If the condition is met on an interface or subinterface, debug command output will be displayed for that interface. The debugging output for an interface is “triggered” when the condition has been met. The debugging output continues to be disabled for the other interfaces. If, at some later time, the condition is met for another interface, the debug output also will become enabled for that interface.
 
       
 Once debugging output has been triggered on an interface, the output will continue until the interface goes down. However, the session for that interface might change, resulting in a new username, called party number, or calling party number. Use the no debug interface command to reset the debug trigger mechanism for a particular interface. The debugging output for that interface will be disabled until the interface meets one of the specified conditions.
 
       
 To limit the number of debugging messages based on a specified condition, use the following command in privileged EXEC mode:
 
       
 
         
          
        
 
          
          
 
            
 Command
 		 
            
 Purpose
 		 
          
 
          
          
          
 
            
Router# debug condition {username username | called dial-string | caller dial-string}
 		 
            
 Enables conditional debugging. The router will display only messages for interfaces that meet this condition.
 		 
          
 
          
        
 
       
 
       
 To reenable the debugging output for all interfaces, enter the no debug condition all command. 
 
      
 
      
 
       
 
       
 
      
 
     
 
    
 
    
 
      
       
     
Specifying Multiple Debugging Conditions
 
     
 
      
 
        
         
       
 To limit the number of debugging messages based on more than one condition, use the following commands in privileged EXEC mode:
 
      
 
       
        
      SUMMARY STEPS 
      
1.    Router# debug condition{username username | called dial-string | caller dial-string}
 
      
2.    Router# debug condition{username username | called dial-string | caller dial-string}
 
      
 
      DETAILED STEPS 
      
 
        
        
 
           
         Command or Action 
         Purpose 
        
 
        
 
          
          
 
           Step 1 
          
 
          
          
 
            Router# debug condition{username username | called dial-string | caller dial-string}  
          
 
          
 Enables conditional debugging, and specifies the first condition.
  		 
        
 
        
 
          
          
 
           Step 2 
          
 
          
          
 
            Router# debug condition{username username | called dial-string | caller dial-string}  
          
 
          
 Specifies the second condition. Repeat this task until all conditions are specified.
  		 
        
 
        
      
 
      What to Do Next 
      
 
 
      
 If you enter multiple debug condition commands, debugging output will be generated if an interface meets at least one of the conditions. If you remove one of the conditions using the no debug condition command, interfaces that meet only that condition no longer will produce debugging output. However, interfaces that meet a condition other than the removed condition will continue to generate output. Only if no active conditions are met for an interface will the output for that interface be disabled.
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
    
 
      
       
     
Conditionally Triggered Debugging Configuration Examples
 
     
 
      
 
        
         
       
 In this example, four conditions have been set by the following commands:
 
        
         
       
     
        
  •   debug condition interface serial 0  
    •  
        
  •   debug condition interface serial 1  
    •  
        
  •   debug condition interface virtual-template 1  
    •  
        
  •   debug condition username fred  
    •  
       
 
       
 The first three conditions have been met by one interface. The fourth condition has not yet been met:
 
       
Router# show debug condition
Condition 1: interface Se0 (1 flags triggered)
        Flags: Se0
Condition 2: interface Se1 (1 flags triggered)
        Flags: Se1
Condition 3: interface Vt1 (1 flags triggered)
        Flags: Vt1
Condition 4: username fred (0 flags triggered)

 
       
 When any debug condition command is entered, debugging messages for conditional debugging are enabled. The following debugging messages show conditions being met on different interfaces as the serial 0 and serial 1 interfaces come up. For example, the second line of output indicates that serial interface 0 meets the username fred condition. 
 
       
*Mar  1 00:04:41.647: %LINK-3-UPDOWN: Interface Serial0, changed state to up
*Mar  1 00:04:41.715: Se0 Debug: Condition 4, username fred triggered, count 2
*Mar  1 00:04:42.963: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to up
*Mar  1 00:04:43.271: Vi1 Debug: Condition 3, interface Vt1 triggered, count 1
*Mar  1 00:04:43.271: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to up
*Mar  1 00:04:43.279: Vi1 Debug: Condition 4, username fred triggered, count 2
*Mar  1 00:04:43.283: Vi1 Debug: Condition 1, interface Se0 triggered, count 3
*Mar  1 00:04:44.039: %IP-4-DUPADDR: Duplicate address 172.27.32.114 on Ethernet 0, sourced by 00e0.1e3e.2d41
*Mar  1 00:04:44.283: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, changed state to up
*Mar  1 00:04:54.667: %LINK-3-UPDOWN: Interface Serial1, changed state to up
*Mar  1 00:04:54.731: Se1 Debug: Condition 4, username fred triggered, count 2
*Mar  1 00:04:54.735: Vi1 Debug: Condition 2, interface Se1 triggered, count 4
*Mar  1 00:04:55.735: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to up

 
       
 After a period of time, the show debug condition command displays the revised list of conditions: 
 
       
Router# show debug condition
Condition 1: interface Se0 (2 flags triggered)
        Flags: Se0 Vi1
Condition 2: interface Se1 (2 flags triggered)
        Flags: Se1 Vi1
Condition 3: interface Vt1 (2 flags triggered)
        Flags: Vt1 Vi1
Condition 4: username fred (3 flags triggered)
        Flags: Se0 Vi1 Se1

 
       
 Next, the serial 1 and serial 0 interfaces go down. When an interface goes down, conditions for that interface are cleared.
 
       
*Mar  1 00:05:51.443: %LINK-3-UPDOWN: Interface Serial1, changed state to down
*Mar  1 00:05:51.471: Se1 Debug: Condition 4, username fred cleared, count 1
*Mar  1 00:05:51.479: Vi1 Debug: Condition 2, interface Se1 cleared, count 3
*Mar  1 00:05:52.443: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to down
*Mar  1 00:05:56.859: %LINK-3-UPDOWN: Interface Serial0, changed state to down
*Mar  1 00:05:56.887: Se0 Debug: Condition 4, username fred cleared, count 1
*Mar  1 00:05:56.895: Vi1 Debug: Condition 1, interface Se0 cleared, count 2
*Mar  1 00:05:56.899: Vi1 Debug: Condition 3, interface Vt1 cleared, count 1
*Mar  1 00:05:56.899: Vi1 Debug: Condition 4, username fred cleared, count 0
*Mar  1 00:05:56.903: %LINK-3-UPDOWN: Interface Virtual-Access1, changed state to down
*Mar  1 00:05:57.907: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to down
*Mar  1 00:05:57.907: %LINEPROTO-5-UPDOWN: Line protocol on Interface Virtual-Access1, changed state to down

 
       
 The final show debug condition output is the same as the output before the interfaces came up:
 
       
Router# show debug condition
Condition 1: interface Se0 (1 flags triggered)
        Flags: Se0
Condition 2: interface Se1 (1 flags triggered)
        Flags: Se1
Condition 3: interface Vt1 (1 flags triggered)
        Flags: Vt1
Condition 4: username fred (0 flags triggered)
 
      
 
     
 
     
 
      
 
      
 
     
 
    
 
   
 
   
 
     
      
    
Using the Environmental Monitor
 
    
 
     
 Some routers and access servers have an environmental monitor that monitors the physical condition of the router. If a measurement exceeds acceptable margins, a warning message is printed to the system console. The system software collects measurements once every 60 seconds, but warnings for a given test point are printed at most once every 4 hours. If the temperature measurements are out of specification more than the shutdown, the software shuts the router down (the fan will remain on). The router must be manually turned off and on after such a shutdown. You can query the environmental monitor using the show environment command at any time to determine whether a measurement is out of tolerance. Refer to the Cisco IOS System Error Messages publication for a description of environmental monitor warning messages.
 
     
 On routers with an environmental monitor, if the software detects that any of its temperature test points have exceeded maximum margins, it performs the following steps:
 
      
       
     
     
      
  1.  Saves the last measured values from each of the six test points to internal nonvolatile memory.
    2.  
      
  2.  Interrupts the system software and causes a shutdown message to be printed on the system console.
    3.  
      
  3.  Shuts off the power supplies after a few milliseconds of delay. 
    4.  
     
 
     
 The system displays the following message if temperatures exceed maximum margins, along with a message indicating the reason for the shutdown:
 
     
Router#
%ENVM-1-SHUTDOWN: Environmental Monitor initiated shutdown
%ENVM-2-TEMP: Inlet temperature has reached SHUTDOWN level at 64(C)

 
     
 Refer to the hardware installation and maintenance publication for your router for more information about environmental specifications.
 
    
 
    
 
     
 
     
 
    
 
   
 
   
 
     
      
    
 
 
    
 
     
 
       
        
      
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R) 
 
      
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.