[BlueOnyx:22318] Re: DNS

[Michael Stauber]

Hi Colin,

> I have been asked by a client to create a new CNAME record on the DNS
> for the following:
> 
> NEW Record Type: CNAME
> 
> Hostname: _69F8BF440B0DA58166380745E0EB4F5F.domain.co.uk
> 
> Point to:
> 57BB458482A5AB33474E97891351014E.E610BBD363C7C2E032B35DDA755B2B52.55WcQD58V50sJqcKeKP5.comodoca.com
> 
> Bind says no! :-/
> 
> It won’t accept either of the host names using the GUI and adding it to
> the include file causes an error.
The regular expressions that the GUI uses to validate input type
"hostname" is like this:

<typedef name="hostname" type="re"

data="^(([a-z0-9]|[a-z0-9][a-z0-9\-]*[a-z0-9])\.)*([a-z0-9]|[a-z0-9][a-z0-9\-]*[a-z0-9])$"

/>

So ... no upper case characters and no leading "_". Granted, we're a bit
more strict there than RFC 952 and RFC 1123, which say that the
characters are case insensitive. Meaning: Put a big "A" there or a small
"a" and it doesn't matter. Both are treated as the same.

Still: The fact remains that host- and domain names (according to RFC)
may not start with anything *but* a character or (as of RFC 1123) a
number. Hence: The underscore is a total no-no.

Unless you're talking domain keys (which are deprecated anyway) or SRV
records.

I guess what your client really wants is either a CAA-record or a
SRV-record and not a C-name?

-- 
With best regards

Michael Stauber