When Enno Rey mentioned RFC 6106 support (why does it matter?) on Cisco IOS during the opening presentation of Troopers 2014 IPv6 security summit I got interested but remained a bit skeptical. When Eric Vyncke (sitting in the audience) started nodding, I knew it must be there. Finding the feature in IOS documentation turned out to be mission impossible.
First try: Google for “RFC 6106 Cisco IOS”. Got a number of hits on Cisco Support Community (and an old blog post of mine), all of them yammering about lack of RFC 6106 support. Also found a new buzzword to look for: RDNSS.
Second try: Google for “RDNSS Cisco IOS”. Same results.
Third try: “RDNSS site:cisco.com” and “RFC 6106 site:cisco.com”. No better
Time to dig into the documentation. IPv6 configuration guides were not exactly useful – no mention of RA and DNS in the same sentence.
Gateway of last resort: IPv6 command reference for IOS XE (IOS XE is usually the first one to get the cool features). I guessed the new gem must be hidden somewhere in the ipv6 nd ra configuration. BINGO! RFC 6106 support is available in IOS XE 3.9S and later and configured with ipv6 nd ra dns server address interface configuration command.
Of course I had to try to figure out where my other searches went wrong, so I searched for “ipv6 nd ra dns server” on cisco.com. Results: a number of useless hits and IPv6 command reference. It looks like nobody took the time to write a configuration guide explaining the new feature.
Looking for more IPv6 goodies?
Check out IPv6 resources page (warning: work in progress) on ipSpace.net.