实现1：标准控制访问列表：用于控制远程计算机TELNET，在默认情况下路由器是不允许任何计算机登录的，开启标准访问列表后就允许指定的IP地址的主机访问。
Router(config)#access-list 50 permit 192.168.1.2
Router(config)#line vty 0 4
in Filter incoming connections
out Filter outgoing connections
Router(config-line)#access-class 50 in
Router(config-line)#line vty 0 4
Router(config-line)#password 1
Router(config-line)#login
结果：
PC>telnet 192.168.1.1
Trying 192.168.1.1 ...
% Connection refused by remote host
PC>
PC>telnet 192.168.1.1
Trying 192.168.1.1 ...Open
User Access Verification
Password:
Router>en
指定对特定的IP主机限制其能否访问外网（阻止）。
Router(config)#access-list 1 deny 192.168.1.2
Router(config)#access-list 1 permit any
Router(config)#int s0/0
Router(config-if)#ip access-group 1 out
结果：没限制前：PC>ping 10.0.0.3
Pinging 10.0.0.3 with 32 bytes of data:
Request timed out.
Reply from 10.0.0.3: bytes=32 time=125ms TTL=126
Reply from 10.0.0.3: bytes=32 time=157ms TTL=126
Reply from 10.0.0.3: bytes=32 time=156ms TTL=126
Ping statistics for 10.0.0.3:
Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
Approximate round trip times in milli-seconds:
Minimum = 125ms, Maximum = 157ms, Average = 146ms
限制后：
PC>ping 10.0.0.3
Pinging 10.0.0.3 with 32 bytes of data:
Reply from 192.168.1.1: Destination host unreachable.
Reply from 192.168.1.1: Destination host unreachable.
Reply from 192.168.1.1: Destination host unreachable.
Reply from 192.168.1.1: Destination host unreachable.
Ping statistics for 10.0.0.3:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss)
实现 2：扩展控制访问列表：对特定的IP地址段的主机限制其访问外网的能力Router(config)#access-list 105 permit icmp 192.168.1.0 0.0.0.255 10.0.0.0 0.0.0.255
Router(config)#int s0/0
Router(config-if)#ip access-group 105 out
限制前192.168.2.0|24主机PC3PC>ping 10.0.0.3
Pinging 10.0.0.3 with 32 bytes of data:
Reply from 10.0.0.3: bytes=32 time=125ms TTL=126
Reply from 10.0.0.3: bytes=32 time=157ms TTL=126
Reply from 10.0.0.3: bytes=32 time=157ms TTL=126
Reply from 10.0.0.3: bytes=32 time=125ms TTL=126
Ping statistics for 10.0.0.3:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 125ms, Maximum = 157ms, Average = 141ms
限制后PC3：
PC>ping 10.0.0.3
Pinging 10.0.0.3 with 32 bytes of data:
Reply from 192.168.2.1: Destination host unreachable.
Reply from 192.168.2.1: Destination host unreachable.
Reply from 192.168.2.1: Destination host unreachable.
Reply from 192.168.2.1: Destination host unreachable.
Ping statistics for 10.0.0.3:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
而192.168.1.0|24网段的PC机配置前后都为：
PC>ping 10.0.0.3
Pinging 10.0.0.3 with 32 bytes of data:
Reply from 10.0.0.3: bytes=32 time=125ms TTL=126
Reply from 10.0.0.3: bytes=32 time=157ms TTL=126
Reply from 10.0.0.3: bytes=32 time=157ms TTL=126
Reply from 10.0.0.3: bytes=32 time=125ms TTL=126
Ping statistics for 10.0.0.3:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 125ms, Maximum = 157ms, Average = 141ms
注：先对端口s0/0 no ip access-group 105 out命令
对特定端口的IP数据包进行过滤（阻止）；
Router(config)#access-list 101 deny tcp any 192.168.2.0 0.0.0.255 eq www
Router(config)#access-list 101 permit tcp any any eq www
Router(config)#int s0/0
Router(config-if)#p access-group 101 out
限制前：
PC>ping 10.0.0.3
Pinging 10.0.0.3 with 32 bytes of data:
Reply from 10.0.0.3: bytes=32 time=157ms TTL=126
Reply from 10.0.0.3: bytes=32 time=141ms TTL=126
Reply from 10.0.0.3: bytes=32 time=125ms TTL=126
Reply from 10.0.0.3: bytes=32 time=125ms TTL=126
Ping statistics for 10.0.0.3:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 125ms, Maximum = 157ms, Average = 137ms
限制后：
PC>ping 10.0.0.3
Pinging 10.0.0.3 with 32 bytes of data:
Reply from 192.168.1.1: Destination host unreachable.
Reply from 192.168.1.1: Destination host unreachable.
Reply from 192.168.1.1: Destination host unreachable.
Reply from 192.168.1.1: Destination host unreachable.
Ping statistics for 10.0.0.3:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
HTTP:
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对特定端口的IP数据包进行过滤（阻止）。
