check-names settings

[Barry Margolin]

In article <gaeumj$gfv$1 at sf1.isc.org>,
 Mark Andrews <Mark_Andrews at isc.org> wrote:

> 	Labels start with a letter or digit.  Labels end with a
> 	letter or digit.  Letter, digit or hypen in the middle of
> 	the label.
> 
> 	All labels meet the above with the exception of a mbox where
> 	second to last labels meet the above.
> 
> 	A single period can also be used as a place marker.
> 
> 	The rules are applied to the owner names of A, AAAA and
> 	MX records.
> 	NS and MX records rdata.
> 	IN-ADDR.ARPA and IP6.ARPA PTR records rdata.
> 	(I don't think I've missed any cases).
> 
> 	Underscore was choosen for SRV records so that they would
> 	*not* clash with hostnames.

Even folks who put underscores in hostnames are practically never going 
to clash with SRV records.  Labels in SRV records *start* with 
underscores, and no one does that with hostnames, even if their 
nameservers allow it.  Underscores, like hyphens in standard-conforming 
hostnames, are always used as word separators in hostnames.

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE don't copy me on replies, I'll read them in the group ***