实验要求：
分别划分inside（内网），outside（外网），dmz（服务器区）三个区
配置PAT，直接使用outside接口的ip地址进行转换
配置静态NAT，发布内网服务器
启用NAT控制，配置NAT豁免，内网访问dmz区中的主机时，不做NAT转换
R1配置：
R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#host outsite
outsite(config)#int f0/0
outsite(config-if)#ip add 12.0.0.2 255.255.255.0
outsite(config-if)#no shut
outsite(config-if)#int f0
00:21:15: %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up
00:21:16: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
outsite(config-if)#int f0/1
outsite(config-if)#ip add 13.0.0.1 255.255.255.0
outsite(config-if)#no shut
outsite(config-if)#
00:21:33: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
00:21:34: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, changed state to up
outsite(config-if)#exit
outsite(config)#ip route 0.0.0.0 0.0.0.0 f0/0
outsite(config)#end
ASA配置：
ciscoasa# conf t
ciscoasa(config)# hostname asa
asa(config)# int e0/0
asa(config-if)# nameif inside
INFO: Security level for "inside" set to 100 by default.
asa(config-if)# ip add 192.168.1.1 255.255.255.0
asa(config-if)# no shut
asa(config-if)# int e0/2
asa(config-if)# nameif outside
INFO: Security level for "outside" set to 0 by default.
asa(config-if)# ip add 12.0.0.1 255.255.255.0
asa(config-if)# no shut
asa(config-if)# int e0/1
asa(config-if)# ip add 192.168.10.1 255.255.255.0
asa(config-if)# no shut
asa(config-if)# nameif dmz
INFO: Security level for "dmz" set to 0 by default.
asa(config-if)# sec
asa(config-if)# security-level 50
asa(config-if)# no shut
asa(config-if)# exit
asa(config)# route outside 0 0 12.0.0.2
ciscoasa# conf t
ciscoasa(config)# nat-control
ciscoasa(config)# nat (inside) 1 192.168.1.0 255.255.255.0
ciscoasa(config)# gl
ciscoasa(config)# global (outside) 1 interface
INFO: outside interface address added to PAT pool
ciscoasa(config)# end
ciscoasa# show xlate
0 in use, 1 most used
ciscoasa# show xlate
1 in use, 1 most used
PAT Global 12.0.0.1(1) Local 192.168.1.2 ICMP id 1
很明显的看出来已经把内网地址转换成外网地址，从而可以让内网用户上网了
Ping不通是因为防火墙的原因，这里需要些acl放行
ciscoasa(config)# access-list 111 permit icmp any any
ciscoasa(config)# acc
ciscoasa(config)# access-g
ciscoasa(config)# access-group 111 in int
ciscoasa(config)# access-group 111 in interface outside
ciscoasa(config)# access-list nonat permit ip host 192.168.1.2 host 192.168.10.10 //豁免nat，也就是说从内网访问到dmz区域的流量不走nat，直接走内网。
ciscoasa(config)# nat (inside) 0 access-list nonat
再次测试就ok了
因为默认高到低是可以通的，所以内网访问dmz区无需配置，测试如下：
静态NAT（发布DMZ区的服务器）一对一的固定转换：
ciscoasa(config)# static (dmz,outside) 12.0.0.3 192.168.10.10
ciscoasa(config)# access-list out_to_dmz permit tcp any host 12.0.0.3 eq www
ciscoasa(config)# access-group out_to_dmz in int outside
ciscoasa(config)# exit
外网验证如下：
本文转自 探花无情 51CTO博客，原文链接:http://blog.51cto.com/983865387/1858570
