Brocade Communications Systems Brocade ICX 6650 6650 - Manual (Page 151)

Brocade ICX 6650 Security Configuration Guide 131
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Configuring an IPv6 ACL
The following commands apply the ACL “rtr” to the incoming traffic on ports 1/2/1 and 1/2/2.
Default and implicit IPv6 ACL action
The default action when no IPv6 ACLs are configured on an interface is to permit all IPv6 traffic.
However, once you configure an IPv6 ACL and apply it to an interface, the default action for that
interface is to deny all IPv6 traffic that is not explicitly permitted on the interface.
• If you want to tightly control access, configure ACLs consisting of permit entries for the access
you want to permit. The ACLs implicitly deny all other access.
• If you want to secure access in environments with many users, you might want to configure
ACLs that consist of explicit deny entries, then add an entry to permit all access to the end of
each ACL. The permit entry permits packets that are not denied by the deny entries.
Every IPv6 ACL has the following implicit conditions as its last match conditions.
• permit icmp any any nd-na – Allows ICMP neighbor discovery acknowledgements.
• permit icmp any any nd-ns – Allows ICMP neighbor discovery solicitations.
• deny ipv6 any any – Denies IPv6 traffic. You must enter a permit ipv6 any any as the last
statement in the access-list if you want to permit IPv6 traffic that were not denied by the
previous statements.
NOTE
If an IPv6 ACL has the implicit deny condition, make sure it also permits the IPv6 link-local address,
in addition to the global unicast address. Otherwise, routing protocols such as OSPF will not work.
To view the link-local address, use the show ipv6 interface command.
The conditions are applied in the order shown above, with deny ipv6 any any as the last condition
applied.
For example, if you want to deny ICMP neighbor discovery acknowledgement, then permit any
remaining IPv6 traffic, enter commands such as the following.
Brocade(config)# show ipv6 access-list rtr
ipv6 access-list rtr: 3 entries
10: deny tcp 2001:db8:21::/24 2001:db8:22::/24
20: deny udp any range rje 6 2001:db8:22::/24
30: permit ipv6 any any
Brocade(config)# interface ethernet 1/2/1
Brocade(config-if-e10000-1/2/1)# ipv6 enable
Brocade(config-if-e10000-1/2/1)# ipv6 traffic-filter rtr in
Brocade(config-if-e10000-1/2/1)# exit
Brocade(config)# interface ethernet 1/2/2
Brocade(config-if-e10000-1/2/2)# ipv6 enable
Brocade(config-if-e10000-1/2/2)# ipv6 traffic-filter rtr in
Brocade(config)# write memory
Brocade(config)# ipv6 access-list netw
Brocade(config-ipv6-access-list-netw)# permit icmp 2001:db8:e0bb::/64
2001:3782::/64
Brocade(config-ipv6-access-list-netw)# deny icmp any any nd-na
Brocade(config-ipv6-access-list-netw)# permit ipv6 any any