[100418] in RedHat Linux List
Re: MX secondary, dns and sendmail - what's wrong?
daemon@ATHENA.MIT.EDU (Godfrey Nix)
Fri Nov 20 12:45:53 1998
From: "Godfrey Nix" <g.nix@emnet.co.uk>
To: redhat-list@redhat.com
Date: Fri, 20 Nov 1998 17:28:01 +0000
Reply-to: g.nix@emnet.co.uk
In-reply-to: <B0000007174@redwood.etool.com>
Resent-From: redhat-list@redhat.com
Yeah, I fully sympathise. I was messed about by a previous supplier myself.
If you have many sub-domains, not just a single domain, then you will
be using a file called sendmail.cw at a guess (It lists all the domains that
the mail server will handle mail for. So probably some of the domains are
missing from that list. It is not enough for DNS to say that the machine will
handle mail for the domain, you have to tell sendmail also.
DNS :
accounts.mydomain.com IN MX 10 serverA.mydomain.com
production.mydomain.com IN MX 10 serverA.mydomain.com
.. same for serverB ..
sendmail.cw - serverA ONLY
mydomain.com
accounts.mydomain.com
production.mydomain.com
sendmail.cw on server B
<only those domains that are to be handled locally>
if you list all the domains as on serverA, then mail will be
delivered locally, as that is what you have asked for
HTH,
Godfrey
>
> Maybe someone can point me in the right direction, 'cause I can't see it.
>
> Our upstream ISP has been listed as a secondary mail forwarder for a few
> years, but they've caused us enough probs that I'm taking it in
> house...but I config'd something wrong and I'm not sure what it is.
>
> First, our dns is like this (this is a pre-BIND8 config file):
>
> mydomain.com IN MX 10 serverA.mydomain.com;
> mydomain.com IN MX 20 serverB.mydomain.com;
>
> I've checked and this ISN'T a DNS-propagation problem. I've also gone
> over my sendmail.cf for correctness.
>
> Two probs: in the cases where I have a user "Drew" on both serverA AND
> serverB, I'm getting some mail delivered locally on serverB (when it
> should be forwarded to serverA). Other messages seem to be getting lost
> altogether.
>
> Secondly, some of our domains are being refused altogether by serverB,
> when they should be forwarded to serverA for local delivery.
>
> What I'm trying for here is for serverB - as a backup - to relay all our
> mail to serverA, but ONLY our various domains, and to refuse to relay
> messages to other outside domains (we've had a prob with scammers using a
> couple of our servers for relaying spam).
>
> Anyone see what I'm missing?
>
> Thanks - Drew
>
>
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>
Godfrey N Nix C.Eng MBCS B.ScTech(Hons) Dip Ed.
Network Operations Manager
East Midlands Network Ltd (emnet)
phone 0115 956 8260
visit http://www.emnet.co.uk
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