Re: Routing restrictions?

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From: Dan Kelley [MSFT] (dankel_at_online.microsoft.com)
Date: 03/11/04 

Date: Thu, 11 Mar 2004 13:30:32 -0500

Hello Dave,

For inbound mail, the Exchange IMS does a reverse DNS lookup by default.
This article mentions how to disable it:

258745 XIMS: Internet Mail Service Displays SMTP Banner Slowly
http://support.microsoft.com/?id=258745

Unfortunately, that will not help here as Susan mentioned as the Exchange
Server is failing to send mail to external domains because the public IP
address for the Exchange Server does not have a reverse DNS record (a.k.a.
PTR or pointer) in the reverse lookup zone. Susan is right that this will
resolve the issue.

There is no configuration in Exchange to disable reverse DNS lookup on an
external receiving server. 

-- 
Regards,
Dan Kelley
Microsoft PSS
Please do not send email directly to this alias. This alias is for newsgroup
purposes only. This posting is provided "AS IS" with no warranties, and
confers no rights.
-----
"Susan VanAllen [MVP]" <svanallen@nospam-mvps.org> wrote in message
news:ecmanR5BEHA.3400@tk2msftngp13.phx.gbl...
> Really Dave? Where is this setting?
> <curious>
>
> "Dave" <anonymous@discussions.microsoft.com> wrote in message
> news:b25201c40793$45a0a780$a501280a@phx.gbl...
> > There is a setting in the Internet Mail Service for
> > Exchange that you can enable to perform a reverse lookup.
> > If the system can not reverse lookup the senders domain on
> > their email address the Exchange server will reject it.
> > After enough rejections the spammer will most likely
> > stop.  It would be better if you could figure out from
> > analyzing the network packets what address(es) they are
> > comming from and block them at a router or switch level
> > before your exchange server has to deal with them.  But
> > that wouldn't be any fun!  Hope this helps.
> >
> > /Dave
> >
> > >-----Original Message-----
> > >Hi
> > >I hope someone can help me with this problem.
> > >I have in my IMS set Reroute incoming SMTP mail, because
> > I have 3 servers
> > >that are allowed to relay (they all have class c ip
> > addresses 192.168)). My
> > >problem is that I get alot of messages stuck in my queues
> > with no originator
> > >and are "spam". I don't know how the get in. I'm running
> > E5.5 sp4 on W2000.
> > >I see in Routing Restrictions that I can set ipaddresses
> > that can NEVER
> > >Route mail. What happens if I enter a lot of class a,b ,c
> > addresses.?
> > >Have I missed somthing in my other settings?
> > >
> > >needs help.
> > >/Mike
> > >
> > >
> > >.
> > >
>
>

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