配置标准命名ACL

命名访问控制列表可以为ACL起一个有意义的名字，通过名称就可以得知该ACL要实现什么功能。同时，因为使用的是名称而不是数字，也就没有了ACL数量上的限制。
网络拓扑如图－7所示：

图－7
步骤
实现此案例需要按照如下步骤进行。
步骤一：将2配置扩展ACL中的扩展访问控制列表移除，其他配置保留

tarena-R1(config)#interface f0/0
tarena-R1(config-if)#no ip access-group 100 in
tarena-R1(config-if)#exit
tarena-R1(config)#no access-list 100

步骤二：在R2上配置标准的命名访问控制列表
命名访问控制列表的配置总体上和用数字表示的ACL一样，但是更加灵活。

tarena-R2(config)#ip access-list standard denypc2
tarena-R2(config-std-nacl)#deny host 192.168.0.20
tarena-R2(config-std-nacl)#permit any
tarena-R2(config-std-nacl)#exit
tarena-R2(config)#interface f0/1
tarena-R2(config-if)#ip access-group denypc2 out

步骤三：分别在PC1和PC2上做连通性测试

PC1测试如下所示：

PC>ipconfig
FastEthernet0 Connection:(default port)
Link-local IPv6 Address.........: FE80::2E0:F7FF:FED6:54CC
IP Address......................: 192.168.0.10
Subnet Mask.....................: 255.255.255.0
Default Gateway.................: 192.168.0.1
PC>ping 192.168.2.100
Pinging 192.168.2.100 with 32 bytes of data:
Reply from 192.168.2.100: bytes=32 time=0ms TTL=126
Reply from 192.168.2.100: bytes=32 time=0ms TTL=126
Reply from 192.168.2.100: bytes=32 time=0ms TTL=126
Reply from 192.168.2.100: bytes=32 time=0ms TTL=126
Ping statistics for 192.168.2.100:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms
PC>

PC2测试如下所示：

PC>ipconfig
FastEthernet0 Connection:(default port)
Link-local IPv6 Address.........: FE80::2D0:BAFF:FE98:9E29
IP Address......................: 192.168.0.20
Subnet Mask.....................: 255.255.255.0
Default Gateway.................: 192.168.0.1
PC>ping 192.168.2.100
Pinging 192.168.2.100 with 32 bytes of data:
Reply from 192.168.1.2: Destination host unreachable.
Reply from 192.168.1.2: Destination host unreachable.
Reply from 192.168.1.2: Destination host unreachable.
Reply from 192.168.1.2: Destination host unreachable.
Ping statistics for 192.168.2.100:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
PC>

输出结果表明，PC1的访问是正常的，而PC2到Web Server的访问被R2（IP地址为192.168.1.2）拒绝。
步骤四：在R2上查看相关的ACL信息

tarena-R2#show ip access-lists 
Standard IP access list denypc2
    10 deny host 192.168.0.20 (4 match(es))
    20 permit any (4 match(es))

输出结果也表明，来自于PC2的数据包被拦截。