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From: keith@spider.co.uk (Keith Mitchell)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Use Domain In Hostname Or Not?
Message-ID: <9002211437.AA01335@orbweb.spider.co.uk>
Date: 21 Feb 90 14:37:34 GMT
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 scs%itivax%ox.com%umich%mailrus%cs.utexas.edu@tut.cis.ohio-state.edu
 (Steve Simmons) writes:

"... I'm interested in any and all comments on why or why not to set
hostname to FQDN...."    (FQDN = Fully Qualified Domain Name)


This is something I have found a bone of contention for a while.  In
theory it shouldn't make any difference if you are running BIND, as
the "domain" directive in /etc/resolv.conf (or /etc/named.boot ?)
should tack it on to any unqualified hostnames you enter. I think the
principle of always using FQDNs is a good one, provided you can have
this short-cut for user input. Naive users certainly don't want to
know about domains.

In practice, however, the implementations are never quite up to it.
For example:

- rshd does not appear to pick up the default domain as above.  So
you have to put a fully qualified name into your ".rhosts" or
"hosts.equiv" even if you're normally used to just the short name.
Ultrix V3 & SCO TCP/IP do this, but Excelan EXOS software gets it
right, and MIPS RISC/os 4.0 has a work-around.

- Some sendmails use the resolver library so that the "$w" (ie this
host's name) macro gets set to the FQDN, others just the basename.
This can lead to delightful behaviour such as:
"HELO redknee.spider.co.uk.spider.co.uk" if the sendmail.cf isn't
smart to it - I have yet to fix mine to get this right.  Here,
Ultrix gets it right, and RISC/os and SCO get it wrong.

Your comment "The vendor agrees their performance isn't correct.."
intrigues me, as in the face of the above diverse behaviour I'm
confused as to what the correct behaviour IS.  If anyone can throw
light on this, or what resolver calls are involved that produce the
above behaviour, I would be very keen to more. We would like to have
consistency in our sendmail.cf files, too.

Other FQDN problems I can think of would be clashes with Yellow
Pages, and the fact (minor one, this) that the domain qualification
can cause visual clutter in for example, "netstat" output. A output
option of "don't qualify hostnames" might be a nice way round this.
(Or how about "only qualify if it's not the local domain" ?)

Anyone else have experience of these ones ?

Keith Mitchell

Spider Systems Ltd.             Spider Systems Inc.
Spider Park    		        12 New England Executive Park
Stanwell Street                 Burlington
Edinburgh, Scotland             MA 01803
+44 31-554 9424                 +1 (617) 270-3510

keith@spider.co.uk              keith%spider.co.uk@uunet.uu.net
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