Newsgroups: comp.mail.sendmail
Path: utzoo!utgpu!cunews!jstewart
From: jstewart@ccs.carleton.ca (John Stewart)
Subject: Re: sendmail & nameservice
Message-ID: <1990Dec21.151027.19467@ccs.carleton.ca>
Organization: Carleton University, Ottawa, Canada
References: <1990Dec21.121210.17836@turnkey.tcc.com>
Date: Fri, 21 Dec 90 15:10:27 GMT

In article <1990Dec21.121210.17836@turnkey.tcc.com> jackv@turnkey.TCC.COM (Jack F. Vogel) writes:
>Can someone tell me why sendmail is coded to be "all or nothing", as it were,
>dependent on the nameserver? What I mean is that the way things are set up,
>if you define NAMED_BIND then getcanonnname() does a res_search() and if that
>fails due to a server being down or whatever then you are SOL, in fact, there
>is no error checking at all. On the other hand, if NAMED_BIND is not defined
>then getcanonname() uses gethostbyname(). Now, at least with AIX the routine
>gethostbyname() will first attempt a nameserver query, and if that fails
>falls back to parsing the host file. 

There are good arguments for having your nameserver database be "the"
authority for the mapping of machine names to IP addresses in your domain.  
If this policy is followed, the hosts file should never contain a mapping that
isn't defined in your nameserver.  

This is the policy we follow here at Carleton.  The transition from host
files to the nameserver as the authority was not entirely smooth, it did
take some time for everyone to understand why they couldn't just add an
entry to the hosts file to allocate an IP address for a new machine.
-- 
---
Artificial Intelligence: What some programmers produce.
Artificial Stupidity:    What the rest of us produce.
