bind 9 and multiple domain names

Question

I have been told the following from someone after trying to get more than one domain name (zone) to work on the same BIND instance. We are able to get a single domain name "example.com" working but cannot get a second domain "example2.com" to work. After research by my co-worker it was determined that BIND 9 does not support multiple domain names. The caveat I was told is if you have more than one interface, you can connect that domain name to the IP on that other interface.

BIND 9.8.2rc1-RedHat-9.8.2-0.23.rc1.el6_5.1;
CentOS release 6.5 (Final)

We have been using BIND for years and never had a problem. Is there any documentation (I looked at the isc docs and did not see it spelled out) to prove/disprove this assertion?

Thanks Brian

Answer 1

This is plain nonsense. Multiple zones per DNS server are supported in BIND 9.x, have been supported since the earliest BIND releases, and every single other DNS server (that I've seen) supports this as well.

• The BIND 9 Administrator Reference Manual does talk about "some zones" (plural) in chapter 1, and even includes an example configuration for three zones on a single server in chapter 3.

  The BIND name server can simultaneously act as a master for some zones, a slave for other zones, and as a caching (recursive) server for a set of local clients.

• Going back in time, the BIND 4.8 source code dated 1987 has an example configuration file "named.boot" that lists three separate zones and a copy of RFC 883 which again talks about a server having multiple zones in the introduction.

• There is also no reason in DNS itself for a one-zone-per-IP limit, as the full domain name gets sent in each query, after all, so the server always knows what it should reply with.

  (Maybe the coworker was thinking of HTTPS on older systems before TLS SNI became widespread?)

You say you cannot get a second domain name to work. Please post a new question and describe the "not working" part in less vague terms (e.g. receiving error messages, wrong answers to queries, etc.), maybe post some BIND syslog messages or dig output showing the problems.