This sample configuration demonstrates how to set up the PIX Firewall for access to a mail server located on the outside 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 applies to these software and hardware versions:
Cisco Secure PIX 500 Series Firewall
PIX Firewall software release 6.3(3)
Cisco 2522 routers
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 6.3(3) !--- These commands name the Ethernet interfaces and !--- define their security levels. 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 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 !--- These commands specify the media type !--- for the interfaces...auto = auto-detect. interface ethernet0 auto interface ethernet1 auto mtu outside 1500 mtu inside 1500 !--- These commands define an IP address for each interface. ip address inside 192.168.1.1 255.255.255.252 ip address outside 18.104.22.168 255.255.255.252 no failover arp timeout 14400 !--- This command defines the global address for the Network Address Translation !--- (NAT) statement. In this case, the two commands state that any traffic !--- from the 192.168.2.x network that passes from the inside interface (Ethernet0) !--- to the outside interface (Ethernet 1) translates into an address !--- in the range of 22.214.171.124 through 126.96.36.199 and contains a subnet !--- mask of 255.255.255.128. global (outside) 1 188.8.131.52-184.108.40.206 netmask 255.255.255.128 !--- This command reserves the last available address (220.127.116.11) for !--- for Port Address Translation (PAT). In the previous statement, !--- each address inside that requests a connection uses one !--- of the addresses specified. If all of these addresses are in use, !--- this statement provides a failsafe to allow additional inside stations !--- to establish connections. global (outside) 1 18.104.22.168 !--- This command indicates that all addresses in the 192.168.2.x range !--- that pass from the inside (Ethernet0) to a corresponding global !--- designation are done with NAT. !--- As outbound traffic is permitted by default on the PIX, no !--- static commands are needed. nat (inside) 1 192.168.2.0 255.255.255.0 !--- Sets the default route for the PIX Firewall at 22.214.171.124. route outside 0.0.0.0 0.0.0.0 126.96.36.199 1 !--- Creates a static route for the 192.168.2.x network with 192.168.1.2. !--- The PIX forwards packets with these addresses to the router !--- at 192.168.1.2. route inside 192.168.2.0 255.255.255.0 192.168.1.2 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 snmp-server host inside 188.8.131.52 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
Current configuration: ! version 12.0 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname 2522-R4 ! enable secret 5 $1$N0F3$XE2aJhJlCbLWYloDwNvcV. ! ip subnet-zero ! ! ! ! ! interface Ethernet0 !--- Assigns an IP address to the inside Ethernet interface. ip address 192.168.2.1 255.255.255.0 no ip directed-broadcast ! interface Ethernet1 !--- Assigns an IP address to the PIX-facing interface. ip address 192.168.1.2 255.255.255.252 no ip directed-broadcast ! interface Serial0 no ip address no ip directed-broadcast shutdown ! interface Serial1 no ip address no ip directed-broadcast shutdown ! ip classless !--- This route instructs the inside router to forward all !--- non-local packets to the PIX. ip route 0.0.0.0 0.0.0.0 192.168.1.1 ! ! line con 0 transport input none line aux 0 autoselect during-login line vty 0 4 exec-timeout 5 0 password ww login ! end
Current configuration: ! version 12.0 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname 2522-R4 ! enable secret 5 $1$N0F3$XE2aJhJlCbLWYloDwNvcV. ! ip subnet-zero ! ! ! ! interface Ethernet0 !--- Assigns an IP address to the PIX-facing Ethernet interface. ip address 184.108.40.206 255.255.255.252 no ip directed-broadcast ! interface Ethernet1 !--- Assigns an IP address to the server-facing Ethernet interface. ip address 220.127.116.11 255.255.255.252 no ip directed-broadcast ! interface Serial0 !--- Assigns an IP address to the Internet-facing interface. ip address 18.104.22.168 255.255.255.252 no ip directed-broadcast no ip mroute-cache ! interface Serial1 no ip address no ip directed-broadcast ! ip classless !--- All non-local packets are to be sent out serial 0. In this case, !--- the IP address on the other end of the serial interface is not known, !--- or you can specify it here. ip route 0.0.0.0 0.0.0.0 serial 0 ! !--- This statement is required to direct traffic destined to the !--- 22.214.171.124 network (the PIX global pool) to the PIX to be translated !--- back to inside addresses. ip route 126.96.36.199 255.255.255.128 188.8.131.52 ! ! 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 mail is a problem, examine the messages to locate the IP addresses of the sending and receiving stations in order to determine the problem.
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Refer to Cisco Technical Tips Conventions for information on conventions used in this document.