DNS and BIND on IPv6

Chapter 5. Troubleshooting

Troubleshooting IPv6-related DNS problems isn’t much different from troubleshooting other DNS problems. The main things you need to know are how to specify the IPv6 address of a name server to query and how to forward-map and reverse-map IPv6 addresses. I’ll show you how to use both nslookup and dig to perform these tasks.

There’s one important thing to keep in mind with either query tool: they default to using IPv4, which means that whether you type nslookup terminator.movie.edu or dig wormhole.movie.edu, the program will look up A records (that is, IPv4 addresses). You need to specify AAAA records explicitly to look up IPv6 addresses. Likewise, nslookup – terminator.movie.edu will send a query to the name server’s IPv4 address, not its IPv6 address. With recent versions of dig, dig @terminator.movie.edu will query the name server’s IPv6 address first, assuming terminator.movie.edu owns a AAAA record.

nslookup

First, I’ll reiterate something we said in DNS and BIND: nslookup is not a great troubleshooting tool for a number of reasons. It insulates you from the details of the DNS message and is prone to displaying errors that are unrelated to the query you’re interested in, such as an inability to reverse-map the address of the name server it’s querying to a domain name. But nslookup is more prevalent than my preferred DNS troubleshooting tool, dig, so I’m obliged to cover it.

First, to query a name server over IPv6, you’ll need to use either nslookup’s