Are underscores no longer supported in Bind 9.4?

Mark Andrews Mark_Andrews at
Thu Mar 1 00:45:13 UTC 2007

> Does bind 9.4 no longer support underscores (_) in the A records?
> I know I have these in many records in versions before 9.4.
> Here is the error that I am getting now.
> Feb 28 18:29:54 t141 named[8767]:
> bad owner name (check-names)
> As soon as I remove the A record with the underscore it in, everything is
> fine and the zone loads.
> Is this a new rule / RFC?

	No.  It's a 20 year old rule.  See RFC 952 and RFC 1123.
	The later extends the syntax to allow leading digits.

	Labels in hostnames are restricted to letters, digits and
	hypens (LDH).

	If you really want underscore you can turn the checks off
	however I suggest that you rename the machines as there are
	resolver libraries which check.

> Thanks,
> -Jake
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at

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