Re: [cobalt-users] Mail Exchange in DMZ

["Jeff Jensen" <jeff@xxxxxxxxxxxxxxxxx>]

To answer Colins questions:

a) The DNS is hosted by a 3rd party.
b) The two Raqs are two seperate domains, they don't have anything to do
with one another.

I just tried from another machine in the DMZ (NT box) to look up the main
site on each of the RAQs in a browser. I can see the correct external IP is
resolved but the browser also times out after a while.  So it's not just a
mail problem. So I think it's a firewall problem.

Jeff
----- Original Message -----
From: "Colin J. Raven" <cjraven@xxxxxxxxxxx>
To: <cobalt-users@xxxxxxxxxxxxxxx>
Sent: Sunday, April 08, 2001 5:52 PM
Subject: Re: [cobalt-users] Mail Exchange in DMZ


> On Sun, 8 Apr 2001, Jeff Jensen wrote:
> > I'm sorry if this isn't a Cobalt question.
>
> Yes, it is a "Cobalt Question" tangentially.
>
> > I have just installed a second RAQ in my DMZ and now have a problem when
> > sending mail between the two machines. In the maillog I can see that the
> > sendmail times out when trying to send mail between the two. I don't
> > have any problems with sending and receiving mail from the Internet on
> > the two Raqs.
>
> As a first guess (and that's what it is) it sounds like there is no
> success on reverse lookup, ergo Sedmail times out attempting to deliver
> the message.
>
> >  I know this has something to do with the machines external IP and the
> > firewall.
>
> Ummm...yes and perhaps also no.
> You said both machines are in the DMZ, so a couple of questions come to
> mind;
> a) How is your DNS set up? (who's handling it...you or a 3rd party?)
> b) To what extent is each machine aware of the other?? Is one machine
> designed to be a failover for the other??? This isn't clear from your
> post...I'm "assuming" (risky) that there isn't a relationship between the
> two. Mail from one machine to the other shouldn't be passing *through* the
> firewall, but maybe just *to* the firewall (then back inside) but again,
> details are thin, so this is speculative at best.
>
> If I were you, I'd begin thinking "behind" the firewall first, especially
> since you say that mail *from* the WAN and *to* the WAN works for each
> machine. In any event, more detail would be useful to begin zeroing in on
> the real cause.
>
> Just my first stab at this, anyone???????
> Hell, as a "cheap date" you could put each  machine's external IP in
> the other's resolv.conf I guess....I gotta try this myself since I have an
> experimental setup somewhat similar at home.
>
> Regards,
> -Colin
> --
> Colin J. Raven
> Linux Registered User #82296
> Sun Apr  8 11:36:00 EDT 2001
>  11:36am  up 39 days, 15:07,  1 user,  load average: 0.02, 0.05, 0.00
>
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