[isalist] Re: SMTP - internal to localhost issue..

  • From: "Thor (Hammer of God)" <thor@xxxxxxxxxxxxxxx>
  • To: "isalist@xxxxxxxxxxxxx" <isalist@xxxxxxxxxxxxx>
  • Date: Wed, 2 Dec 2009 16:46:55 -0800

Don't listen to Steve.  He's on crack.   I'm assuming you're servers are SNAT 
clients (int ISA nic is their default gateway) since you are publishing...  you 
should be able to telnet to 25 on your server's external published address just 
fine as long as your rules allow that.   I just telnet'ed from my Exchange box 
itself to its externally published address and it worked just fine.   What do 
your ISA logs say?

t

From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On 
Behalf Of Paul T. Laudenslager
Sent: Wednesday, December 02, 2009 4:33 PM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Re: SMTP - internal to localhost issue..

Okay... Hmm...

Let's say I have a bunch of customers on ServerA and a different bunch on 
ServerB.

If customers on ServerA send customers on ServerB an email, the ServerA server 
resolves the IP address to the "external" or "public" IP, not the 
internal/local IP.

I don't want to have to have maintain an entire DNS to resolve hundreds of 
domain names internally.  I thought I had this configuration working several 
times before... maybe I'm wrong.

One way that does work is to implement a mail relay server outside the 
firewall.  However, that means all internal smtp traffic from one mail server 
to another has to go outside the firewall.

There just seems something wrong with that.

Me wanna worky! :)
-paul
________________________________
From: isalist-bounce@xxxxxxxxxxxxx [isalist-bounce@xxxxxxxxxxxxx] On Behalf Of 
Steve Moffat [Steve@xxxxxxxxxx]
Sent: Wednesday, December 02, 2009 7:14 PM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] Re: SMTP - internal to localhost issue..
Don't try to do that through ISA...no worky....

From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On 
Behalf Of Paul T. Laudenslager
Sent: Wednesday, December 02, 2009 8:11 PM
To: isalist@xxxxxxxxxxxxx
Subject: [isalist] SMTP - internal to localhost issue..


Okay, I'm missing something simple here but have yet to figure it out.



1.  I published (2) internal SMTP boxes to outside "live" IP addresses.  I can 
access these internal servers on port 25 just fine on thier 'public' ips.



2.  I can telnet to the SMTP port of each other's private IP address.  (ie. 
172.16.x.x to 172.16.x.x)



Problem

======



When I try and telnet from one SMTP server to the published "public" IP of the 
other SMTP server, the connection is denied.



I've created a rule to allow internal network to localhost network for port 25 
but it is still failing.



Any suggestions on what to look for next?



Thanks in advance for your kind suggestions! :)

-paul





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