Is @ valid in any part of the zone file?

Question

e.g. can I do

subdomain IN CNAME @

in a zone file? or is it only valid in the beginning of a record? e.g

@ IN TXT "v=spf1 a mx -all"

Answer 1

@ is legal both as an "owner name" (i.e. the name of a zone file entry) and as "rdata" (i.e. the contents of a DNS entry), but only as a standalone token.

What you cannot do is <label>.@ - there's no need because <label> on its own with no trailing dot will implicitly append the current value of @ (aka $ORIGIN).

Answer 2

Have a look at this page. They did not say explicitly whether it is allowed or not to have @ at the end in your DNS record. You can try it yourself and see if it works!

EDIT:

It seems legal to have at the end. I found an example on Wikipedia.