IPv6ACL规则如下：
1 只能使用命名的ACL
2 ACL序号匹配由小到大
3 默认情况下，隐含permit icmp any any nd-na 和permit icmp anyany nd-ns 用于邻居发现协议的邻居通告和邻居请求，允许接口发送和接收IPv6邻居发现包。
3 结尾默认隐含 deny ipv6 any any
4 使用命令ipv6 traffic-filter应用于接口的in or out方向
需求：在R1配置ACL，禁止R1的环回接口访问R4的环回接口地址；
ACL配置如下，其它配置略：
R1(config)#ipv6 access-list Mao
R1(config-ipv6-acl)#deny 2011::1/1282044::4/128
R1(config-ipv6-acl)#permit any any
R1(config)#int fa0/0
R1(config-if)#ipv6 traffic-filter Mao out
R1#show ipv6 access-list
IPv6 access list Mao
deny ipv6 host 2011::1 host 2044::4 sequence 10
permit ipv6 anyany sequence 20
R1#ping 2044::4 source 2011::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2044::4,timeout is 2 seconds:
Packet sent with a source address of2011::1
!!!!!
Success rate is 100 percent (5/5),round-trip min/avg/max = 24/36/52 ms
为什么会ping通呢？是因为命令ipv6 traffic-filter的作用是过滤路由器转发的流量，但不过滤源自本路由器的流量；
现在将ACL进行修改如下，拒绝从R4环回接口发回来的数据包，并将ACL应用至fa0/0的入接口方向上；
R1(config)#ipv6access-list Mao
R1(config-ipv6-acl)#no deny ipv6 host 2011::1 host 2044::4
R1(config-ipv6-acl)#deny ipv6 2044::4/128 2011::1/128
R1(config-ipv6-acl)#permit any any
R1(config-if)#no ipv6 traffic-filter Mao out
R1(config-if)#ipv6 traffic-filter Mao in
R1#ping2044::4 source 2011::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2044::4,timeout is 2 seconds:
Packet sent with a source address of2011::1
.....
Success rate is 0 percent (0/5)
R1#show access-lists
IPv6 access list Mao
deny ipv6 host 2044::4 host 2011::1 (5 matches) sequence 30 //匹配了5个数据包
permit ipv6 anyany (4 matches) sequence 40
总结：命令ipv6traffic-filter不过滤源自本路由器的流量，因此在配置IPv6 ACL时需要注意流量的起源是否来至本路由器。
以上例子也可以在R3上配置，如下：
R3(config)#ipv6access-list Mao
R3(config-ipv6-acl)#deny ipv6 2011::1/128 2044::4/128
R3(config-ipv6-acl)#permit any any
R3(config)#int fa0/1
R3(config-if)#ipv6 traffic-filter Mao out
R1#ping 2044::4 source 2011::1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2044::4,timeout is 2 seconds:
Packet sent with a source address of2011::1
SSSSS
Success rate is 0 percent (0/5)
不通，在R1和R3之间抓包可知，如下图：
ICMPv6的类型为1，表示目标不可达，代码字段为5，源地址被入站/出站策略所阻止。
