This sample configuration demonstrates how to set up the PIX Firewall for access to a mail server located on the inside network.
Note: The SMTP inspection configured in this document is not compatible with ESMTP connections to servers such as Microsoft Exchange. Do not configure SMTP inspection if you use a mail server that relies on ESMTP. Alternatively, PIX Software version 7.0 and later supports SMTP and ESMTP inspection.
There are no specific requirements for this document.
The information in this document is based on these software and hardware versions:
PIX Firewall 10000
PIX Firewall software release 5.1(4)
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.
This document uses this network setup.
This document uses these configurations.
PIX Version 5.1(4) !--- These commands name and set the security level for each PIX interface. nameif ethernet0 outside security0 nameif ethernet1 inside security100 enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted hostname PIX_1 domain-name noplace.com fixup protocol ftp 21 fixup protocol http 80 fixup protocol h323 1720 fixup protocol rsh 514 fixup protocol smtp 25 fixup protocol sqlnet 1521 no names !--- Create an access list that permits SMTP traffic from anywhere !--- to the host at 220.127.116.11 (our server). The name of this list is !--- smtp. Add additional lines to this access list as required. !--- Note: There is one and only one access list allowed per !--- interface per direction (for example, inbound on the outside interface). !--- Because of limitation, any additional lines that need placement in !--- the access list need to be specified here. If the server !--- in question is not SMTP, replace the occurrences of SMTP with !--- www, DNS, POP3, or whatever else is required. The access-list !--- command was introduced in PIX Software Release 5.0; it is used !--- here instead of a conduit statement. access-list smtp permit tcp any host 18.104.22.168 eq smtp pager lines 24 logging on logging timestamp no logging standby logging console debugging logging monitor debugging logging buffered debugging logging trap debugging no logging history logging facility 23 logging queue 512 !--- Set each Ethernet interface to auto-detect its media type. interface ethernet0 auto interface ethernet1 auto mtu outside 1500 mtu inside 1500 !--- Define the IP address for each interface. ip address inside 192.168.1.1 255.255.255.0 ip address outside 22.214.171.124 255.255.255.252 no failover arp timeout 14400 !--- Specify that any traffic that originates inside from the !--- 192.168.2.x network NATs (PAT) to 126.96.36.199 if !--- such traffic passes through the outside interface. global (outside) 1 188.8.131.52 nat (inside) 1 192.168.2.0 255.255.255.0 !--- Define a static translation between 192.168.2.57 on the inside and !--- 184.108.40.206 on the outside. These are the addresses to be used by !--- the server located inside the firewall. static (inside,outside) 220.127.116.11 192.168.2.57 netmask 255.255.255.255 !--- Apply the access list named smtp inbound on the outside interface. access-group smtp in interface outside !--- Set the default route to 18.104.22.168. !--- The PIX assumes that this address is that of a router. route outside 0.0.0.0 0.0.0.0 22.214.171.124 1 !--- Instruct the PIX to hand any traffic destined for 192.168.x.x !--- to the router at 192.168.1.2. route inside 192.168.0.0 255.255.0.0 192.168.1.2 1 timeout xlate 1:30:00 conn 1:00:00 half-closed 0:10:00 udp 0:00:00 timeout rpc 0:10:00 h323 0:05:00 timeout uauth 0:00:00 absolute aaa-server TACACS+ protocol tacacs+ aaa-server RADIUS protocol radius no snmp-server location no snmp-server contact snmp-server community public no snmp-server enable traps floodguard enable terminal width 200 Cryptochecksum:d66eb04bc477f21ffbd5baa21ce0f85a : end !--- Alternate command: !--- conduit permit tcp host 126.96.36.199 eq smtp any !--- The conduit command is equivalent to !--- the access-list statements this configuration shows. !--- In this case a path known as a conduit is created in order to allow any SMTP !--- traffic to host 188.8.131.52. Use of this command replaces the !--- access-list and access-group !--- statements that this configuration presents.
Current configuration: ! version 12.0 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname 2522-R5 ! enable secret 5 $1$N0F3$XE2aJhJlCbLWYloDwNvcV. ! ip subnet-zero ! ! ! ! ! interface Ethernet0 !--- Sets the IP address of the Ethernet interface to 184.108.40.206. ip address 220.127.116.11 255.255.255.252 ! interface Serial0 !--- Instructs the serial interface to use !--- the address of the Ethernet interface when the need arises. ip unnumbered ethernet 0 ! interface Serial1 no ip address no ip directed-broadcast ! ip classless !--- Instructs the router to send all traffic !--- destined for 209.164.3.x to 18.104.22.168. ip route 22.214.171.124 255.255.255.0 126.96.36.199 !--- Instructs the router to send !--- all other remote traffic out serial 0. ip route 0.0.0.0 0.0.0.0 serial 0 ! ! line con 0 transport input none line aux 0 autoselect during-login line vty 0 4 exec-timeout 5 0 password ww login ! end
There is currently no verification procedure available for this configuration.
The logging console debugging command directs messages to the PIX console. If connectivity to the mail server is a problem, examine the console debug messages to locate the IP addresses of the sending and receiving stations in order to determine the problem.
|If you still need assistance after you complete the troubleshooting steps in this document and want to open a case with Cisco Technical Support, be sure to include this information for troubleshooting your PIX Firewall.|
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Refer to Cisco Technical Tips Conventions for information on conventions used in this document.