Re: Sender Spoofing via SMTP

["Gaddis, Jeremy L." <jeremy () linuxwiz net>]

brandon.steili () gmail com wrote:
> Hi List,
>
> I know this is a common issue that does not seem to be well addressed, but I was hoping you folks could give some 
> suggestions. (preferably for Exchange 2003)
>
> If I telnet to a system on the internet and perform the following:

[snip]

Exchange 2003 will not relay by default (not sure about previous 
versions).  If you want to have your mail servers tested to see if you 
are an open relay, telnet to "relay-test.mail-abuse.org" from the mail 
server itself.  The remote server will connect back to your box on 
port 25 and run a series of tests that finishes up with a summary line 
of whether you're configured as an open relay.

Check Microsoft's TechNet archive as they have numerous articles on 
preventing others from using your Exchange servers as an open relay.

HTH,
-j

--
Jeremy L. Gaddis   <jeremy () linuxwiz net>
Senior Systems Engineer
LinuxWiz Consulting

"If it's not on fire, it's a software problem."