Nerd blog.

10 Mar 2013

OSPF and IPv6

Having recently setup BGP for a new IPv6 space, I wanted to make sure that IPv6 wasn’t a “second class citizen” on the network, so it needed to be routed redundantly internally as well. I picked a /48 to pull subnets out of for routing, and then matched up the 4th quad with the VLAN ID for administration ease and simplicity.

The important commands are as follows:

ipv6 unicast-routing

ipv6 router ospf 6
 redistribute connected
 redistribute static

interface VlanXX
 ipv6 address XXXX:XXXX:X:XX::2/64
 ipv6 ospf 6 area

ipv6 access-list secure6_ssh
 permit ipv6 2001:DB8:D00D::/48 any
 deny ipv6 any any

line vty 5 15
 ipv6 access-class secure6_ssh in

This sets up an interface for OSPF, setup up an ACL for secure ssh access over IPv6, and sets up IPv6 OSPF routing process ID 6. It is a good idea to specify a router-id, because if your router has no IPv4 addresses it will not be able to pick a router-id and never form adjacencies.

I like that all the ipv6 related commands on Cisco all start with ipv6, ipv6 address, ipv6 access-list, ipv6 router, ipv6 ospf, etc etc. It is nice that they were able to unify all the commands under one heading.

Theodore Baschak - Theo is a network engineer with experience operating core internet technologies like HTTP, HTTPS and DNS. He has extensive experience running service provider networks with OSPF, MPLS, and BGP.