Re: Blocking SMTP Port 25

From: Lanwench [MVP - Exchange] (lanwench_at_heybuddy.donotsendme.unsolicitedmail.atyahoo.com)
Date: 06/30/04 

Date: Tue, 29 Jun 2004 20:45:47 -0400

Jeff L wrote:
> Lanwrench,
>
> Are you saying that he should be blocking relays through ISA. I
> agree. Are you suspecting he is an open relay?
>
> Most of the virus attacks we are blocking coming in on Port 25 are
> wrapped in emails coming from spammers. We deny connections from
> known spammers in order to cut down on viruses and still receive
> email from legitimate sources. This is done through Exchange, do you
> agree?

Yes - and Exchange 2003 is not an open relay by default (altho' everyone
ought to disable authenticated relay, too, unless absolutely necessary &
only leave it enabled *if* complex passwords are used w/regular pw changes &
guest is left disabled). It was my understanding from the original post that
they wanted to prevent any outbound SMTP traffic on their network from any
box other than their Exchange server.
>
> Jeff Loucks
> Available Technology ®
> Solutions For Professionals ®
> www.availabletechnology.com
>
>
> "Lanwench [MVP - Exchange]"
> <lanwench@heybuddy.donotsendme.unsolicitedmail.atyahoo.com> wrote in
> message news:OG$ziJjXEHA.3596@tk2msftngp13.phx.gbl...
>> Your firewall or ISA server is where you need to set this....
>>
>> Jon R wrote:
>>> Hi, I'm looking to block port 25 for outgoing traffic which doesnt
>>> originate from the SBS 2000 server. Can anyone point me in the right
>>> direction on this?
>>>
>>> Thanks

Relevant Pages

  • Re: ISA 2006 and Exchange 2007 Anti-Spam
    ... Jim Harrison (ISA SE) ... Exchange server. ... I am to assume that I should forego the open relay ...
    (microsoft.public.isaserver)
  • Re: FO: I/O card with matching relay unit
    ... There are lots of older boxes that have at least a couple of ISA slots. ... mains on and off I'd use a separate second relay or triac circuit. ... 3A/24V DC load capability will easily drive a separate mains relay, ...
    (uk.adverts.computer)
  • Re: smtp relay & isa server 2004
    ... > Hi Simone, ... > Get a second NIC in that ISA firewall as you're good to go -- lots of docs ... If I have an ISA server 2004 in single nic mode, ... run an SMTP relay on the same box? ...
    (microsoft.public.isaserver)
  • Re: Exchange 2003 -> ISA 2004
    ... jedoch weiterhin die Fehlermeldung im ISA Protokollierungslog: ... SMTP fehlgeschlagener Verbindungsversuch auf PORT 25. ... > eigenes Relay auf dem ISA Server einrichten möchte. ...
    (microsoft.public.de.german.isaserver)
  • Re: sendmail and "sender domain must exist" error
    ... Jeff Lasman wrote: ... "relay" and they don't "relay":D ... sendmail, my confidence is up! ... I'll revisit configuring sendmail or postfix as a SMTP server. ...
    (RedHat)
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