smtp authentication/open relay question

smtp authentication/open relay question

Post by James Swaffor » Fri, 29 Nov 2002 07:29:14


I'm having a problem with my SMTP server;
here's the situation:

Initially, I could only get things "working"
if I set the authentication in the SMTP virtual
server to "anonymous", and open up the relay
restrictions.  At this point, I could send/
receive email, but obviously I wanted to close
the open relay.

As per Knowledge Base Article 319267, I added a
second SMTP virtual server (named "Client
Access Server") and set the authentication on
that server to "anonymous", then went back to
the Default virtual server and set the authentication
to "basic."

I only have one internal IP address on the server.
If I bind that IP address to the Default SMTP
virtual server, and bind the new "Client Access Server"
to all unassigned IPs, it forces the client to
authenticate in order to send out email, but
I can't _receive_ email.

Conversely, if I bind the (only) internal IP to
the Client Access Virtual Server and bind all
unassigned IP's to the Default, I can send and
receive fine, but the box is vulnerable to spammers
(I tested via telnet'ing into port 25).

I _think_ I can solve this problem as follows,
but I wanted to bounce it off the good folks in
this newsgroup first. :)

If I add another network card to the server,
and then bind the new IP to the Client Access server
(the one with anonymous authentication), and direct
traffic on port 25 to the _other_ IP (bound
to the Default server with Basic authentication),
will I then be able to send/receive ok with


I hope this is clear... I'd be glad to elaborate.
I really need to close this open relay soon!

Happy Thanksgiving folks,



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