简介
此示例配置展示如何设置Cisco PIX防火墙，来访问位于外部网络的邮件服务器。
请参阅 PIX/ASA 7.x 及更高版本：在网络内部配置示例的邮件服务器访问为了设置访问的PIX/ASA安全工具对在网络内部查找的mail/SMTP服务器。
与邮件服务器访问的参考的PIX/ASA 7.x在DMZ网络配置示例为了设置访问的PIX/ASA安全工具对在DMZ网络查找的mail/SMTP服务器。
请参阅 ASA 8.3及以上版本：在外部网络配置示例的邮件(SMTP)服务器访问关于在Cisco可适应安全工具(ASA)的相同配置的更多信息有版本8.3和以上的。
本文档没有任何特定的要求。
使用的组件
本文档中的信息基于以下软件和硬件版本：
PIX 防火墙 535
PIX 防火墙软件 7.1(1) 版
Cisco 2500 Routers
本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始(默认)配置。如果您使用的是真实网络，请确保您已经了解所有命令的潜在影响。
有关文档规则的详细信息，请参阅 Cisco 技术提示规则。
相关产品
此配置也可用于运行版本 7.x 及更高版本的自适应安全设备 (ASA)。
配置
本部分提供有关如何配置本文档所述功能的信息。
注意：请使用Cisco CLI分析器得到关于用于此部分的命令的更多信息。
网络图
本文档使用以下网络设置：
配置
本文档使用以下配置：
PIX防火墙
PIX Version 7.1(1)
!
hostname pixfirewall
enable password 8Ry2YjIyt7RRXU24 encrypted
names
!
interface Ethernet0
shutdown
no nameif
no security-level
no ip address
!
interface Ethernet1
shutdown
no nameif
no security-level
no ip address
!
interface Ethernet2
shutdown
no nameif
no security-level
no ip address
!
!--- Define the IP address for the inside interface.
interface Ethernet3
nameif inside
security-level 100
ip address 192.168.1.1 255.255.255.252
!
!--- Define the IP address for the outside interface.
interface Ethernet4
nameif outside
security-level 0
ip address 209.64.3.1 255.255.255.252
!
interface Ethernet5
shutdown
no nameif
no security-level
no ip address
!
passwd 2KFQnbNIdI.2KYOU encrypted
ftp mode passive
pager lines 24
mtu inside 1500
mtu outside 1500
no failover
no asdm history enable
arp timeout 14400
!--- This command defines the global 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 209.64.3.129 through 209.64.3.253 and contains a subnet !--- mask of 255.255.255.128.
global (outside) 1 209.64.3.129-209.64.3.253 netmask 255.255.255.128
!--- This command reserves the last available address (209.64.3.254) 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) 1 209.64.3.254
!--- 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
!--- 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
!--- Sets the default route for the PIX Firewall at 209.64.3.2.
route outside 0.0.0.0 0.0.0.0 209.64.3.2 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00
timeout mgcp-pat 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart
telnet timeout 5
ssh timeout 5
console timeout 0
!
class-map inspection_default
match default-inspection-traffic
!
!
!--- SMTP/ESMTP is inspected since "inspect esmtp" is included in the map.
policy-map global_policy
class inspection_default
inspect dns maximum-length 512
inspect ftp
inspect h323 h225
inspect h323 ras
inspect rsh
inspect rtsp
inspect esmtp
inspect sqlnet
inspect skinny
inspect sunrpc
inspect xdmcp
inspect sip
inspect netbios
inspect tftp
!
service-policy global_policy global
Cryptochecksum:8a63de5ae2643c541a397c2de7901041
: end
路由器 A
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
路由器 B
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 209.64.3.2 255.255.255.252
no ip directed-broadcast
!
interface Ethernet1
!--- Assigns an IP address to the server-facing Ethernet interface.
ip address 209.64.3.5 255.255.255.252
no ip directed-broadcast
!
interface Serial0
!--- Assigns an IP address to the Internet-facing interface.
ip address 209.64.3.9 255.255.255.252
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 !--- 209.64.3.128 network (the PIX global pool) to the PIX to be translated !--- back to the inside addresses.
ip route 209.64.3.128 255.255.255.128 209.64.3.1
!
!
line con 0
transport input none
line aux 0
autoselect during-login
line vty 0 4
exec-timeout 5 0
password ww
login
!
end
ESMTP TLS 配置
注意：如果对电子邮件通信使用传输层安全 (TLS) 加密，则 PIX 中的 ESMTP 检查功能(默认情况下启用)将丢弃数据包。要允许在启用了 TLS 功能的情况下使用电子邮件，请禁用 ESMTP 检查功能，如此输出所示。
pix(config)#policy-map global_policy
pix(config-pmap)#class inspection_default
pix(config-pmap-c)#no inspect esmtp
pix(config-pmap-c)#exit
pix(config-pmap)#exit
当前没有可用于此配置的验证过程。
确定Cisco CLI分析程序支持显示命令。请使用CLI分析器查看show命令输出分析。
注意：使用 debug 命令之前，请参阅有关 Debug 命令的重要信息。
logging console debugging 命令将邮件导向到 PIX 控制台。如果与邮件服务器的连接有问题，请检查控制台调试消息，查找发送站和接收站的 IP 地址以便确定问题所在。
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