Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!boulder!ccncsu!longs.LANCE.ColoState.Edu!steved
From: steved@longs.LANCE.ColoState.Edu (Steve Dempsey)
Newsgroups: comp.mail.sendmail
Subject: Re: sendmail.cf file for HP 9000/835.
Message-ID: <3167@ccncsu.ColoState.EDU>
Date: 13 Nov 89 20:30:37 GMT
References: <SIVAGNAN.89Nov11185009@handel.CS.ColoState.Edu>
Sender: news@ccncsu.ColoState.EDU
Reply-To: steved@longs.LANCE.ColoState.Edu (Steve Dempsey)
Organization: Colorado State U. Center for Computer Assisted Engineering
Lines: 59

In article <SIVAGNAN.89Nov11185009@handel.CS.ColoState.Edu>,
sivagnan@handel.CS.ColoState.Edu (S. Vasanthan) writes:
> 
> We don't have 
> (BIND) running, if we cannot resolve address
> we want to forward to some place where it can
> be resolved.
> 

Many people try to do it this way:

	normal address resolution
        deliver if remote address known
            else punt to smarter host
        deliver local stuff

The non-trivial `if remote address known' test does not exist and
the `else punt...' will not work because an unknown address is an
error.  What you can do is this:

        normal address resolution
        handle well-defined set of known addresses
        punt remaining remote addresses to smarter host
        deliver local stuff
        
In sendmail language, this looks like:

   #file containing list of neighboring hosts
   FL/usr/lib/localneighbors

   # for known hosts
   Mether, P=[IPC], F=msDFMuCX, S=11, R=21, A=IPC $h

   ###  Machine dependent part of ruleset zero  ###
   # Deliver to neighbors
   R$*<@$=L>$*                $#ether $@$2 $:$1<@$2>$3
   R$*<@$=L.LOCAL>$*          $#ether $@$2 $:$1<@$2>$3

   # possibly other known domains dealt with here
   
   # alternate method
   R$*<$@$+.local.dom.ain>    $#ether $@$2 $:$1<@$2.local.dom.ain>

   # punt to server
   R$*<@$+>$*            $#ether  $@your.fave.smart.host $:$1<@$2>$3

   # remaining stuff should all be local       
   R$+                   $#local $:$1
   
Of course I've left out all the basic stuff every sendmail.cf needs.
And if you don't care about the added load on your smart host, you can
just hand off everything and let the other guy worry about it.  I do
this and only have to maintain two (client & server) sendmail.cf's.

                       
        Steve Dempsey,  Center for Computer Assisted Engineering
  Colorado State University, Fort Collins, CO  80523    +1 303 491 0630
INET: steved@longs.LANCE.ColoState.Edu, dempsey@handel.CS.ColoState.Edu
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