++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++ sendmail-mailertable~DNS-FAQ.txt ++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Date: Wed, 24 Apr 1996 19:50:36 +0200 (MET DST) From: Leif Erlingsson To: Stephen Subject: Re: Mail Queue Howto question On Tue, 23 Apr 1996, Stephen wrote: > At 11:40 AM 4/21/96 +0200, you wrote: > > >I have a setup with mailertables + my own added rules that > >skips DNS lookup for hosts in mailertable. This only works > >for hosts in the table, and for hosts in Cw, but for no other. > > > >Have You tried FEATURE(`nodns') ? > > Mailertables wouldn't work as a general solution, since I want > to avoid doing all DNS lookups on outgoing mail. Ah, but I wrote " + my own added rules that skips DNS "! (I use these rules a lot - they are additions to the various domain files we use. [These additions are part of the cf/m4/proto.m4 patches at http://www.lege.com/proto.html -- go there -- get'em!]) > I have tried > FEATURE(`nodns'). I'm not sure what its exact function is, but > I believe it only turns off certain resolver options, but not > all DNS lookups. In any case, it didn't solve my problem. > > The problem seems to be with the design of sendmail. It allows > you to declare outgoing mail as "expensive" and queue it, but > it seems the programmers didn't forsee the possibility that > connections for DNS could also be "expensive". In other words, > they assume DNS is always available, so they always do DNS > lookups even when they know the mail will be queued. I guess > this isn't unreasonable, since most TCP/IP protocols depend on > DNS, SMTP included. Maybe I should try using UUCP for outgoing? Why not set up caching only DNS on Your own host?! I am going to do that on mine. [I later tried that and it kind of worked but with all the DNS timeouts I was better off witout any local name- server when offline, so I now have it deactivated again. /Leif.] > >No. But sendmail would play a big part. What is the full name > >of the list? > > Its full address is majordomo@vger.rutgers.edu. If you want to > subscribe, put "subscribe linux-diald" in the body of the > message. Thanks. / Leif Erlingsson ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++ END OF sendmail-mailertable~DNS-FAQ.txt ++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++