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From: demel@TUNAMEA.TUWIEN.AC.AT (Johannes Demel)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: name handling in DNS resolvers
Message-ID: <9105181918.AA13399@tunamea.tuwien.ac.at>
Date: 18 May 91 19:18:23 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 39

I understand that the automatic generation of a domain search list may
not be unique and results in domains which cannot be reached simply.
(at least some implementations of the automatic generation use a trailing
dot to escape from the autmatic generation which solved the problem of
uniqueness, but it is not very userfriendly and it is no solution for
sendmail).
An the other hand the implementationin PC/TCP ist not userfriendly too.
At our University (domain tuwien.ac.at) we have part of the "private"
hosts in the departments and general purpose hosts with services for the
whole university located directly below the domain-name of the university.
But we have an increasing number of hosts (and PC's) which are located
within subdomains (i.e. one more level in the domain-name) assigned to
a department. This makes it easy to assign unique names for the whole 
university (currently approx. 600 hosts) and allows the delegation of
management of the host-names. But this departments have to pay the
price to specify the full domain-name for general service hosts, which is
frustating. 
But there is a well known method to solve the problem without getting
problems with the uniqueness and without requiring 8-16 kbytes of memory.
You can define a list of domains, which may be appended to a name given
which does not contain a dot. E.g. I may define the list
     kom.tuwien.ac.at
     tuwien.ac.at

An for the hostname abc the following names are checked:
     abc.kom.tuwien.ac.at
     abc.tuwien.ac.at
But if the specify the hostname   abc.xy   only
     abc.xy
will be checked.
Something like this method is implemented in cisco-routers.


---
Johannes Demel   demel@edvz.tuwien.ac.at   demel@tunamea.tuwien.ac.at
Computing Center, Head of Communications Group
Technical University Vienna
Wiedner Hauptstrasse 8-10/020, A-1040 Wien, Austria
Tel:  +43 (222) 58801-5829      Fax:  +43 (222) 5874211