ASA 8.3(x): Connect Three Internal Networks with Internet Configuration Example

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Updated:June 9, 2011

Document ID:113041

Bias-Free Language

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Introduction

Prerequisites

Requirements

Components Used

Conventions

Configure

Network Diagram

ASA 8.3 Configuration

ASA 8.3 and Later Configuration

Verify

Troubleshoot

Troubleshooting Commands

Related Information

Introduction

This document provides information on how to set up the Cisco Adaptive Security Appliance (ASA) with version 8.3(1) for use with three internal networks. Static routes are used on the routers for simplicity.

Refer to PIX/ASA : Connecting Three Internal Networks with Internet Configuration Example for the same configuration on Cisco Adaptive Security Appliance (ASA) with versions 8.2 and earlier.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on the Cisco Adaptive Security Appliance (ASA) with version 8.3(1).

The information presented in this document was created from devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If you are working in a live network, ensure that you understand the potential impact of any command before using it.

Conventions

Refer to Cisco Technical Tips Conventions for more information about document conventions.

Configure

In this section, you are presented with the information to configure the features described in this document.

Note: To find additional information on the commands used in this document, use the Command Lookup Tool (registered customers only) .

Network Diagram

This document uses this network setup.

Note: The default gateway of the hosts on the 10.1.1.0 network points to RouterA. A default route on RouterB is added that points to RouterA. RouterA has a default route that points to the ASA inside interface.

Note: The IP addressing schemes used in this configuration are not legally routable on the Internet. They are RFC 1918 addresses that have been used in a lab environment.

ASA 8.3 Configuration

This document uses these configurations.

If you have the output of a write terminal command from your Cisco device, you can use Output Interpreter (registered customers only) to display potential issues and fixes.

RouterA Configuration
RouterB Configuration
ASA 8.3 and Later Configuration

RouterA Configuration
RouterA#show running-config Building configuration... Current configuration : 1151 bytes ! version 12.4 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname RouterA ! boot-start-marker boot-end-marker ! enable password cisco ! memory-size iomem 25 no network-clock-participate slot 1 no network-clock-participate wic 0 no network-clock-participate wic 1 no network-clock-participate wic 2 no network-clock-participate aim 0 no network-clock-participate aim 1 no aaa new-model ip subnet-zero ip cef ! ! ! ! ip audit po max-events 100 no ftp-server write-enable ! ! ! ! ! no crypto isakmp enable ! ! ! interface FastEthernet0/0 ip address 10.1.1.2 255.255.255.0 duplex auto speed auto ! interface FastEthernet0/1 ip address 10.2.1.1 255.255.255.0 duplex auto speed auto ! interface IDS-Sensor1/0 no ip address shutdown hold-queue 60 out ! ip classless ip route 0.0.0.0 0.0.0.0 10.1.1.1 ip route 10.3.1.0 255.255.255.0 10.1.1.3 no ip http server no ip http secure-server ! ! ! ! ! control-plane ! ! ! line con 0 line 33 no activation-character no exec transport preferred none transport input all transport output all line aux 0 line vty 0 4 password ww login ! ! end RouterA#

RouterA Configuration

RouterA#show running-config 
Building configuration...

Current configuration : 1151 bytes
!
version 12.4
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname RouterA
!
boot-start-marker
boot-end-marker
!
enable password cisco
!
memory-size iomem 25
no network-clock-participate slot 1 
no network-clock-participate wic 0 
no network-clock-participate wic 1 
no network-clock-participate wic 2 
no network-clock-participate aim 0 
no network-clock-participate aim 1 
no aaa new-model
ip subnet-zero
ip cef
!
!
!
!
ip audit po max-events 100
no ftp-server write-enable
!
!
!
!
! 
no crypto isakmp enable
!
!
!
interface FastEthernet0/0
ip address 10.1.1.2 255.255.255.0
duplex auto
speed auto
!
interface FastEthernet0/1
ip address 10.2.1.1 255.255.255.0
duplex auto
speed auto
!
interface IDS-Sensor1/0
no ip address
shutdown
hold-queue 60 out
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.1.1.1
ip route 10.3.1.0 255.255.255.0 10.1.1.3
no ip http server
no ip http secure-server
!
!
!
!
!
control-plane
!
!
!
line con 0
line 33
no activation-character
no exec
transport preferred none
transport input all
transport output all
line aux 0
line vty 0 4
password ww
login
!
!
end

RouterA#

RouterB Configuration
RouterB#show running-config Building configuration... Current configuration : 1132 bytes ! version 12.4 no service pad service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname RouterB ! boot-start-marker boot-end-marker ! ! no network-clock-participate slot 1 no network-clock-participate wic 0 no network-clock-participate wic 1 no network-clock-participate wic 2 no network-clock-participate aim 0 no network-clock-participate aim 1 no aaa new-model ip subnet-zero ip cef ! ! ! ! ip audit po max-events 100 no ip domain lookup no ftp-server write-enable ! ! ! ! ! no crypto isakmp enable ! ! ! interface FastEthernet0/0 ip address 10.1.1.3 255.255.255.0 duplex auto speed auto no cdp enable ! interface FastEthernet0/1 ip address 10.3.1.1 255.255.255.0 duplex auto speed auto ! interface IDS-Sensor1/0 no ip address shutdown hold-queue 60 out ! ip classless ip route 0.0.0.0 0.0.0.0 10.1.1.2 no ip http server no ip http secure-server ! ! ! ! ! control-plane ! ! ! line con 0 stopbits 1 line 33 no activation-character no exec transport preferred none transport input all transport output all line aux 0 line vty 0 4 password cisco login ! ! end RouterB#

RouterB Configuration

RouterB#show running-config
Building configuration...

Current configuration : 1132 bytes
!
version 12.4
no service pad
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname RouterB
!
boot-start-marker
boot-end-marker
!
!
no network-clock-participate slot 1 
no network-clock-participate wic 0 
no network-clock-participate wic 1 
no network-clock-participate wic 2 
no network-clock-participate aim 0 
no network-clock-participate aim 1 
no aaa new-model
ip subnet-zero
ip cef 
!
!
!
!
ip audit po max-events 100
no ip domain lookup
no ftp-server write-enable
!
!
!
!
! 
no crypto isakmp enable
!
!
!
interface FastEthernet0/0
ip address 10.1.1.3 255.255.255.0
duplex auto
speed auto
no cdp enable
!
interface FastEthernet0/1
ip address 10.3.1.1 255.255.255.0
duplex auto
speed auto
!
interface IDS-Sensor1/0
no ip address
shutdown
hold-queue 60 out
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.1.1.2
no ip http server
no ip http secure-server
!
!
!
!
!
control-plane
!
!
!
line con 0
stopbits 1
line 33
no activation-character
no exec
transport preferred none
transport input all
transport output all
line aux 0
line vty 0 4
password cisco
login
!
!
end

RouterB#

ASA 8.3 and Later Configuration

Note: Non-default commands are shown in bold.

ASA 8.3(1) Running Config
ASA#show run : Saved : ASA Version 8.3(1) ! hostname ASA enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted names ! interface Ethernet0 nameif outside security-level 0 ip address 10.165.200.225 255.255.255.224 ! interface Ethernet1 nameif inside security-level 100 ip address 10.1.1.1 255.255.255.0 ! boot system disk0:/asa831-k8.bin ftp mode passive !--- Output Suppressed !--- Creates an object called OBJ_GENERIC_ALL. !--- Any host IP not already matching another configured !--- object will get PAT to the outside interface IP !--- on the ASA (or 10.165.200.226) for internet bound traffic. object network OBJ_GENERIC_ALL subnet 0.0.0.0 0.0.0.0 nat (inside,outside) source dynamic OBJ_GENERIC_ALL interface !--- Output Suppressed !--- Define a default route to the ISP router. route outside 0.0.0.0 0.0.0.0 10.165.200.226 1 !--- Define a route to the INTERNAL router with network 10.2.1.0. route inside 10.2.1.0 255.255.255.0 10.1.1.2 1 !--- Define a route to the INTERNAL router with network 10.3.1.0. route inside 10.3.1.0 255.255.255.0 10.1.1.3 1 : end

ASA 8.3(1) Running Config

ASA#show run
: Saved
:
ASA Version 8.3(1)
!
hostname ASA
enable password 8Ry2YjIyt7RRXU24 encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
names
!
interface Ethernet0
 nameif outside
 security-level 0
 ip address 10.165.200.225 255.255.255.224
!
interface Ethernet1
 nameif inside
 security-level 100
 ip address 10.1.1.1 255.255.255.0
!
boot system disk0:/asa831-k8.bin

ftp mode passive


!--- Output Suppressed





!--- Creates an object called OBJ_GENERIC_ALL. !--- Any host IP not already matching another configured !--- object will get PAT to the outside interface IP !--- on the ASA (or 10.165.200.226) for internet bound traffic.


object network OBJ_GENERIC_ALL 
subnet 0.0.0.0 0.0.0.0  
nat (inside,outside) source dynamic OBJ_GENERIC_ALL interface



!--- Output Suppressed



 !--- Define a default route to the ISP router.


route outside 0.0.0.0 0.0.0.0 10.165.200.226 1


 !--- Define a route to the INTERNAL router with network 10.2.1.0.


route inside 10.2.1.0 255.255.255.0 10.1.1.2 1


 !--- Define a route to the INTERNAL router with network 10.3.1.0.


route inside 10.3.1.0 255.255.255.0 10.1.1.3 1

: end

Note: For more information about the configuration of NAT and PAT on ASA 8.3, refer to Information About NAT.

For more information on how to configure access lists on PIX/ASA, refer to PIX/ASA 7.x : Port Redirection (Forwarding) with nat, global, static and access-list Commands.

debug icmp traceâShows whether ICMP requests from the hosts reach the PIX. You need to add the access-list command to permit ICMP in your configuration in order to run this debug.
logging buffer debuggingâShows connections being established and denied to hosts that go through the PIX.? The information is stored in the PIX log buffer and the output can be seen using the show log command.

Refer to Setting Up the PIX Syslog for more information on how to set up logging.