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Cisco IOS Cookbook, 2nd Edition by Ian Brown, Kevin Dooley

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Filtering IPv6

Problem

You want to filter IPv6 traffic using access-lists.

Solution

Cisco supports named access-lists for IPv6:

Router1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#ipv6 access-list EXAMPLES
Router1(config-ipv6-acl)#permit ipv6 AAAA:5::/64 any
Router1(config-ipv6-acl)#permit ipv6 host AAAA:5::FE:1 any
Router1(config-ipv6-acl)#permit tcp any any eq telnet established
Router1(config-ipv6-acl)#deny tcp any any eq telnet syn
Router1(config-ipv6-acl)#sequence 55 permit udp any any eq snmp
Router1(config-ipv6-acl)#remark this is a comment
Router1(config-ipv6-acl)#sequence 66 remark this comment has a sequence number
Router1(config-ipv6-acl)#permit icmp any any reflect ICMP-REFLECT
Router1(config-ipv6-acl)#deny ipv6 any host AAAA:6::1 log
Router1(config-ipv6-acl)#deny ipv6 any any log-input
Router1(config-ipv6-acl)#exit
Router1(config)#interface FastEthernet0/0
Router1(config-if)#ipv6 traffic-filter EXAMPLES in
Router1(config-if)#exit
Router1(config)#end
Router1#

Discussion

The ACL shown in this example isn’t particularly useful, but it does show many of the features available with IPv6 access-lists. There are only named IPv6 access-lists, as numbered lists do not exist. However, as we previously saw in Recipes 19.11 and 19.15, this is not a drawback. Anything you can do with numbered access-lists, you can do with named access-lists, and several features such as reflexive access-lists and the ability to edit individual lines ...

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