preventing return emails from a smart relay host

[UNIX Engr]

Hello,
I have a internet facing sendmail server, HPUX 11i, 8.11 that has a smart relay host configured. The smart relay host is an anti-virus server that connects to an internal Novell groupwise server. The Groupwise server actually delivers the email internally.

How does the smart relay option really work?

When an email is received for an invalid user, it gets through the smart relay to our internal mail server (at least a connection is created to the server on port 25) where the message is found to have an invalid username and this info is returned to sendmail and then the message is returned by sendmail to the original sender.

Does the message actually make it through a smart relay to the internal mail server?

I want to prevent any return to sender messages and I have already configured the sendmail.cf with the following:
# LUSER-RELAY
# UNCOMMENT THE FOLLOWING TWO LINES:
Kuser user -m -a<>
DLlocal:nobody
#
#ALSO UNCOMMENT THE FOLLOWING 2 RULES ....
# send unrecognized local users to a relay host
R< > $+ $: < $L > $(user $1 $) look up user
R< $* > $+ <> $: < > $2 found; strip $L


I am still returning messages about invalid users to the senders..

Thank you for your help.

Steve

[Steven E. Protter]

Smart relay works like this:

in sendmail.cf

DShostname_of_relay_server

or

DS
[IP address of relay server]

example

DSrelayserver.your.net

DS
[192.168.0.20]

I prefer IP address because I can send mail even with DNS offline.

Save the sendmail.cf file

/sbin/init.d/sendmail stop
/sbin/init.d/sendmail start


Now all of this is useless if the intended relay server is not configured to relay for the server we've just configured.

Due to spam concerns the default setup for mail servers is not not permit relay. The admin of the relay server needs to explicitly allow for smart relay.

Diags:

sendmail -v -d8.99 -d38.99 someone@aol.com

type some text

.


This will get you full errors and diagnostics on the command line. If you get an error from this test, you can post it here and get guidance.

SEP