On: How to use dig

[kortex]

Ahhh yup, that makes perfect sense given how zone files are formatted.

But that moves the question. Why do zone files use ; as comment? Some old assembly dialect? I've not worked much with assembly but it's always been # or //

[fanf2 → kortex]

The original DNS implementation (called JEEVES) was written by Paul Mockapetris to run on the PDP-10, which is why the zone file syntax is not very unixy. The ; comments are one example: and backslash escapes are decimal rather than octal, line continuation uses () instead of escaping.

[throw0101a → fanf2]

Straight from the source:

> @jpmens @bortzmeyer @PowerDNS_Bert @kolkman The ";" was the comment delimiter in the TOPS-20 word, hash was dragged in by the UNIX types

* https://twitter.com/svnr2000/status/659062798681546752

See also RFC 883, "Domain Names - Implementation and Specification":

> ; Semicolon is used to start a comment; the remainder of the line is ignored.

* https://datatracker.ietf.org/doc/html/rfc883

Via:

* https://jpmens.net/2015/10/28/the-semicolon-in-zone-master-f...

[throw0101a → kortex]

> @jpmens @svnr2000 ; was chosen as a comment in zone files because that's what the PDP10 and other macro assemblers used in those days.

* https://twitter.com/paulvixie/status/659934566883328000

Via:

* https://jpmens.net/2015/10/28/the-semicolon-in-zone-master-f...

[detaro → kortex]

; is quite common in assembly as the comment marker. And zone files are old, so the // or # were not as standard as they are today.

[jvolkman → kortex]

Maybe the original creator was an Emacs fan? Lisp also uses semicolons for comments.