What is the point of the zones.rfc1918 file for Bind9?

Question

Using an Ubuntu 10.04 LTS server in a standalone environment and trying to use views to serve two different subnets of clients. Getting errors regarding the zones.rfc1918 file, so I'd like to know what that file is used for. What's the point of hosting the rfc1918 addresses?

The subnets I'm using are rfc 1918 addresses, btw. Will including the default zones.rfc1918 file cause me any (more) headaches?

Solution

It is generally considered a good practice to serve localhost, 0.0.127.in-addr.arpa and the RFC-1918 reverse zones on your internal DNS system to prevent sending queries from them out to the internet. It saves time (you get replies for those queries quickly), bandwidth (no requests leaving your network for zones that shouldn't exist), and relieves the load on servers upstream of you.

If you are using RFC-1918 addresses by all means serve the appropriate reverse data for the range(s) you use. You should also serve empty zones (or wildcarded zones) for the other ranges.

Comments

[womble]

The answers you're looking for are all provided in RFC1912, section 4.1.

[voretaq7]

@womble - Oddly (or perhaps not if you consider their relative numbers :) RFC 1912 doesn't specify that you should always have the RFC 1918 zones -- I was looking for an informative or standards-track RFC that says you should, but all I could find are the comments in the default named.conf file that comes with FreeBSD

[womble]

@voretaq7: I've always read RFC1912 in such a way that it's principles apply to RFC1918 addressing (along with other blocks that weren't specified then, such as 192.0.2.0/24 and certain IPv6 netblocks.

[voretaq7]

@womble - as have I, and I've always considered it to be Right and Proper Good Practice, but I've never found an RFC that explicitly says "You should serve the RFC-1918 zones locally so you don't bother your upstream DNS servers (you feckless twits!)". Perhaps I should submit one... can you say "feckless twits" in an IETF RFC? :)