This configuration allows a central Cisco Secure PIX Firewall to communicate with networks behind two other PIX Firewall boxes through VPN tunnels over the Internet or any public network using IPsec. The two outlying networks have no need to communicate with each other, but there is connectivity to the central network. The two outlying networks are not able to communicate with each other by going through the central PIX because the PIX does not route traffic received on one interface back out the same interface. If there is a need for the outlying networks to communicate with each other, you need a fully meshed configuration, instead of the hub and spoke configuration shown in this document. There might already be nat 1, global, static, and conduit statements present on the PIXes. This example only shows the addition of encryption.
For IPsec to work, you must establish connectivity between tunnel endpoints before you start this configuration.
The information in this document is based on PIX Firewall versions 5.1.x , 5.2.x, and 6.3.3.
Note: The show version command must show that encryption is enabled.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Refer to the Cisco Technical Tips Conventions for more information on document conventions.
In this section, you are presented with the information to configure the features described in this document.
Note: Use the Command Lookup Tool (registered customers only) to obtain more information on the commands used in this section.
This document uses this network setup:
This document uses these configurations:
PIX Central |
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Building configuration... : Saved : PIX Version 6.3(3) interface ethernet0 auto interface ethernet1 auto nameif ethernet0 outside security0 nameif ethernet1 inside security100 enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted hostname pix-central fixup protocol dns maximum-length 512 fixup protocol ftp 21 fixup protocol h323 h225 1720 fixup protocol h323 ras 1718-1719 fixup protocol http 80 fixup protocol rsh 514 fixup protocol rtsp 554 fixup protocol sip 5060 fixup protocol sip udp 5060 fixup protocol skinny 2000 fixup protocol smtp 25 fixup protocol sqlnet 1521 fixup protocol tftp 69 names !--- This is traffic to PIX 2. access-list 120 permit ip 10.1.1.0 255.255.255.0 10.2.2.0 255.255.255.0 !--- This is traffic to PIX 3. access-list 130 permit ip 10.1.1.0 255.255.255.0 10.3.3.0 255.255.255.0 !--- Do not do Network Address Translation (NAT) on traffic to other PIXes. access-list 100 permit ip 10.1.1.0 255.255.255.0 10.2.2.0 255.255.255.0 access-list 100 permit ip 10.1.1.0 255.255.255.0 10.3.3.0 255.255.255.0 pager lines 24 logging on mtu outside 1500 mtu inside 1500 ip address outside 172.18.124.153 255.255.255.0 ip address inside 10.1.1.1 255.255.255.0 ip audit info action alarm ip audit attack action alarm pdm history enable arp timeout 14400 !--- Do not do NAT on traffic to other PIXes. nat (inside) 0 access-list 100 route outside 0.0.0.0 0.0.0.0 172.18.124.1 1 timeout xlate 3:00:00 timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00 timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00 timeout uauth 0:05:00 absolute aaa-server TACACS+ protocol tacacs+ aaa-server RADIUS protocol radius aaa-server LOCAL protocol local no snmp-server location no snmp-server contact snmp-server community public snmp-server enable traps floodguard enable sysopt connection permit-ipsec crypto ipsec transform-set myset esp-des esp-md5-hmac !--- This is traffic to PIX 2. crypto map newmap 20 ipsec-isakmp crypto map newmap 20 match address 120 crypto map newmap 20 set peer 172.18.124.154 crypto map newmap 20 set transform-set myset !--- This is traffic to PIX 3. crypto map newmap 30 ipsec-isakmp crypto map newmap 30 match address 130 crypto map newmap 30 set peer 172.18.124.157 crypto map newmap 30 set transform-set myset crypto map newmap interface outside isakmp enable outside isakmp key ******** address 172.18.124.154 netmask 255.255.255.255 no-xauth no-config-mode isakmp key ******** address 172.18.124.157 netmask 255.255.255.255 no-xauth no-config-mode isakmp identity address isakmp policy 10 authentication pre-share isakmp policy 10 encryption des isakmp policy 10 hash md5 isakmp policy 10 group 1 isakmp policy 10 lifetime 1000 telnet timeout 5 ssh timeout 5 console timeout 0 terminal width 80 Cryptochecksum:d41d8cd98f00b204e9800998ecf8427e : end |
PIX 2 |
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Building configuration... : Saved : PIX Version 6.3(3) interface ethernet0 auto interface ethernet1 auto nameif ethernet0 outside security0 nameif ethernet1 inside security100 enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted hostname pix2 fixup protocol dns maximum-length 512 fixup protocol ftp 21 fixup protocol h323 h225 1720 fixup protocol h323 ras 1718-1719 fixup protocol http 80 fixup protocol rsh 514 fixup protocol rtsp 554 fixup protocol sip 5060 fixup protocol sip udp 5060 fixup protocol skinny 2000 fixup protocol smtp 25 fixup protocol sqlnet 1521 fixup protocol tftp 69 names !--- This is traffic to PIX Central. access-list 110 permit ip 10.2.2.0 255.255.255.0 10.1.1.0 255.255.255.0 !--- Do not do NAT on traffic to PIX Central. access-list 100 permit ip 10.2.2.0 255.255.255.0 10.1.1.0 255.255.255.0 pager lines 24 logging on mtu outside 1500 mtu inside 1500 ip address outside 172.18.124.154 255.255.255.0 ip address inside 10.2.2.1 255.255.255.0 ip audit info action alarm ip audit attack action alarm no failover failover timeout 0:00:00 failover poll 15 no failover ip address outside no failover ip address inside pdm history enable arp timeout 14400 !--- Do not do NAT on traffic to PIX Central. nat (inside) 0 access-list 100 route outside 0.0.0.0 0.0.0.0 172.18.124.1 1 timeout xlate 3:00:00 timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00 timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00 timeout uauth 0:05:00 absolute aaa-server TACACS+ protocol tacacs+ aaa-server RADIUS protocol radius aaa-server LOCAL protocol local no snmp-server location no snmp-server contact snmp-server community public no snmp-server enable traps floodguard enable sysopt connection permit-ipsec crypto ipsec transform-set myset esp-des esp-md5-hmac !--- This is traffic to PIX Central. crypto map newmap 10 ipsec-isakmp crypto map newmap 10 match address 110 crypto map newmap 10 set peer 172.18.124.153 crypto map newmap 10 set transform-set myset crypto map newmap interface outside isakmp enable outside isakmp key ******** address 172.18.124.153 netmask 255.255.255.255 no-xauth no-config-mode isakmp identity address isakmp policy 10 authentication pre-share isakmp policy 10 encryption des isakmp policy 10 hash md5 isakmp policy 10 group 1 isakmp policy 10 lifetime 1000 telnet timeout 5 ssh timeout 5 console timeout 0 terminal width 80 Cryptochecksum:d41d8cd98f00b204e9800998ecf8427e : end |
PIX 3 |
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Building configuration... : Saved : PIX Version 6.3(3) interface ethernet0 auto interface ethernet1 auto nameif ethernet0 outside security0 nameif ethernet1 inside security100 enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted hostname pix3 fixup protocol dns maximum-length 512 fixup protocol ftp 21 fixup protocol h323 h225 1720 fixup protocol h323 ras 1718-1719 fixup protocol http 80 fixup protocol rsh 514 fixup protocol rtsp 554 fixup protocol sip 5060 fixup protocol sip udp 5060 fixup protocol skinny 2000 fixup protocol smtp 25 fixup protocol sqlnet 1521 fixup protocol tftp 69 names !--- This is traffic to PIX Central. access-list 110 permit ip 10.3.3.0 255.255.255.0 10.1.1.0 255.255.255.0 !--- Do not do NAT on traffic to PIX Central. access-list 100 permit ip 10.3.3.0 255.255.255.0 10.1.1.0 255.255.255.0 pager lines 24 logging on mtu outside 1500 mtu inside 1500 ip address outside 172.18.124.157 255.255.255.0 ip address inside 10.3.3.1 255.255.255.0 ip audit info action alarm ip audit attack action alarm no failover failover timeout 0:00:00 failover poll 15 no failover ip address outside no failover ip address inside pdm history enable arp timeout 14400 !--- Do not do NAT on traffic to PIX Central. nat (inside) 0 access-list 100 route outside 0.0.0.0 0.0.0.0 172.18.124.1 1 timeout xlate 3:00:00 timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00 timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00 timeout uauth 0:05:00 absolute aaa-server TACACS+ protocol tacacs+ aaa-server RADIUS protocol radius aaa-server LOCAL protocol local no snmp-server location no snmp-server contact snmp-server community public no snmp-server enable traps floodguard enable sysopt connection permit-ipsec crypto ipsec transform-set myset esp-des esp-md5-hmac !--- This is traffic to PIX Central. crypto map newmap 10 ipsec-isakmp crypto map newmap 10 match address 110 crypto map newmap 10 set peer 172.18.124.153 crypto map newmap 10 set transform-set myset crypto map newmap interface outside isakmp enable outside isakmp key ******** address 172.18.124.153 netmask 255.255.255.255 no-xauth no-config-mode isakmp identity address isakmp policy 10 authentication pre-share isakmp policy 10 encryption des isakmp policy 10 hash md5 isakmp policy 10 group 1 isakmp policy 10 lifetime 1000 telnet timeout 5 ssh timeout 5 console timeout 0 terminal width 80 Cryptochecksum:aa3bbd8c6275d214b153e1e0bc0173e4 : end |
Use this section to confirm that your configuration works properly.
The Output Interpreter Tool (registered customers only) (OIT) supports certain show commands. Use the OIT to view an analysis of show command output.
show crypto ipsec sa—Displays the current status of the IPsec security associations (SAs) and is useful in determining if traffic is encrypted.
pix-central#show crypto ipsec sa interface: outside Crypto map tag: newmap, local addr. 172.18.124.153 local ident (addr/mask/prot/port): (10.1.1.0/255.255.255.0/0/0) remote ident (addr/mask/prot/port): (10.3.3.0/255.255.255.0/0/0) current_peer: 172.18.124.157:500 PERMIT, flags={origin_is_acl,} !--- This verifies that encrypted packets are sent !--- and received without any errors. #pkts encaps: 4, #pkts encrypt: 4, #pkts digest 4 #pkts decaps: 4, #pkts decrypt: 4, #pkts verify 4 #pkts compressed: 0, #pkts decompressed: 0 #pkts not compressed: 0, #pkts compr. failed: 0, #pkts decompress failed: 0, #send errors 0, #recv errors 0 local crypto endpt.: 172.18.124.153, remote crypto endpt.: 172.18.124.157 path mtu 1500, ipsec overhead 56, media mtu 1500 current outbound spi: 3bcb6913 !--- Shows inbound SAs that are established. inbound esp sas: spi: 0x3efbe540(1056695616) transform: esp-des esp-md5-hmac , in use settings ={Tunnel, } slot: 0, conn id: 3, crypto map: newmap sa timing: remaining key lifetime (k/sec): (4607999/27330) IV size: 8 bytes replay detection support: Y inbound ah sas: inbound pcp sas: !--- Shows outbound SAs that are established. outbound esp sas: spi: 0x3bcb6913(1003186451) transform: esp-des esp-md5-hmac , in use settings ={Tunnel, } slot: 0, conn id: 4, crypto map: newmap sa timing: remaining key lifetime (k/sec): (4607999/27321) IV size: 8 bytes replay detection support: Y outbound ah sas: outbound pcp sas: local ident (addr/mask/prot/port): (10.1.1.0/255.255.255.0/0/0) remote ident (addr/mask/prot/port): (10.2.2.0/255.255.255.0/0/0) current_peer: 172.18.124.154:500 PERMIT, flags={origin_is_acl,} !--- This verifies that encrypted packets are sent !--- and received without any errors. #pkts encaps: 4, #pkts encrypt: 4, #pkts digest 4 #pkts decaps: 4, #pkts decrypt: 4, #pkts verify 4 #pkts compressed: 0, #pkts decompressed: 0 #pkts not compressed: 0, #pkts compr. failed: 0, #pkts decompress failed: 0, #send errors 0, #recv errors 0 local crypto endpt.: 172.18.124.153, remote crypto endpt.: 172.18.124.154 path mtu 1500, ipsec overhead 56, media mtu 1500 current outbound spi: da8d556 !--- Shows inbound SAs that are established. inbound esp sas: spi: 0x53835c96(1401117846) transform: esp-des esp-md5-hmac , in use settings ={Tunnel, } slot: 0, conn id: 1, crypto map: newmap sa timing: remaining key lifetime (k/sec): (4607999/27319) IV size: 8 bytes replay detection support: Y inbound ah sas: inbound pcp sas: !--- Shows outbound SAs that are established. outbound esp sas: spi: 0xda8d556c(3666695532) transform: esp-des esp-md5-hmac , in use settings ={Tunnel, } slot: 0, conn id: 2, crypto map: newmap sa timing: remaining key lifetime (k/sec): (4607999/27319) IV size: 8 bytes replay detection support: Y outbound ah sas: outbound pcp sas:
show crypto isakmp sa—Shows the current state of the Internet Key Exchange (IKE) SAs.
pix-central#show crypto isakmp sa Total : 2 Embryonic : 0 dst src state pending created 172.18.124.153 172.18.124.154 QM_IDLE 0 0 172.18.124.153 172.18.124.157 QM_IDLE 0 0
This section provides information you can use to troubleshoot your configuration.
Note: Refer to Important Information on Debug Commands before you use debug commands.
On the PIX (with the logging monitor debugging or logging console debugging commands running):
debug crypto ipsec—Debugs IPsec processing.
debug crypto isakmp—Debugs Internet Security Association and Key Management Protocol (ISAKMP) processing.
debug crypto engine—Displays debug messages about crypto engines, which perform encryption and decryption.
Use these commands in the config mode of the PIX:
clear [crypto] ipsec sa—Deletes the active IPsec SAs. The keyword crypto is optional.
clear [crypto] isakmp sa—Deletes the active IKE SAs. The keyword crypto is optional.
Revision | Publish Date | Comments |
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1.0 |
15-Jun-2006 |
Initial Release |