First-hop security IPv6 Cisco IOS

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IPv6 RA Guard

IPv6 Router Advertisement Guard.

IPv6 RA guard provides support for allowing the network administrator to block or reject unwanted or rogue RA guard messages that arrive at the network switch platform. RAs are used by routers to announce themselves on the link.

RA Guard on Routers

From IOS 12.2(33)SXI4 to 12.2(54)SG

R1(config)#<input>int fa0/1</input>
R1(config-if)<input>ipv6 nd raguard</input>

From IOS 12.2(54)SG

R1(config)#<input>int fa0/1</input>
R1(config-if)<input>ipv6 nd raguard policy policy1</input>
R1(config-ra-guard)#

RA Guard on switches

SW1(config)#<input>ipv6 access-list BlockRA</input>
SW1(config-acl)#<input>deny icmp any any router-advertisement</input>
SW1(config-acl)#<input>permit ipv6 any any</input>
SW1(config-acl)#<input>exit</input>
SW1(config)#<input>interface range GigabitEthernet0/1 - 24</input>
SW1(config)#<input>ipv6 traffic-filter BlockRA in</input>

Blocking Rouge DHCPv6 Servers

To block the unwanted DHCPv6 servers.

SW1(config)#<input>ipv6 access-list BlockDHCPv6</input>
SW1(config-acl)#<input>deny udp any eq 546</input>
SW1(config-acl)#<input>permit ipv6 any any</input>
SW1(config-acl)#<input>exit</input>
SW1(config)#<input>interface range GigabitEthernet0/1 - 24</input>
SW1(config)#<input>ipv6 traffic-filter BlockDHCPv6 in</input>

Unicast Reverse Path Forwarding

To avoid spoofed packets passing a Router. Could be DoS attack. With RPF - reverse Path Forwarding - the router checks that the sending hosts source IP address matches the routing table on the receiving interface.

Example

An access-list can be used as an option to this command

R1(config)#<input>interface fa0/1</input>
R1(config-if)#<input>ipv6 verify unicast reverse-path</input>

Links

• Cisco Ipv6 first-hop security