What's the meaning of '@' in a DNS zone file?

Question

I have the following data in my DNS zone file for my domain:

$ORIGIN mydomain.com.
@       IN      A       208.X.Y.Z
mail    IN      A       208.X.Y.Z
... etc..

What does the @ line mean? I know what an A record is.. but a host with an ampersand at sign?

Answer 1

RFC 1035 defines the format of a DNS zone file.

... on page 35 you'll find:

@ A free standing @ is used to denote the current origin.

This means that @ is a shortcut for the name defined with $ORIGIN.

You can find more information on $ORIGIN here, which is an excerpt from Pro DNS and BIND, published by Apress.

Answer 2

It's the root, or in your example it's mydomain.com.

Answer 3

It's an alias for the zone name itself. In this case, it indicates that the zone name has that address (or mx record, or ...)