Hi everybody,

I am a linux-(no-longer-totally-)newbie.

I am a bit confused about my sendmail configuration. When reading the LogWatch, i can see that on a particular day 111 messages are sent. I have a small server with 5 users. I am pretty sure they didn't sent out 111 messages in one day. I would like to be sure that my server cannot be used as a spamming machine.

I have my own MX record for my domain, and this domain is in the /etc/mail/access file, as well as my internal IP-network.

Can I check somehow if i set it up correctly, or can I assume that my server cannot be used for spamming by external users?

I searched the web on this matter, but i must say that it's not very clear how this works.

Thanks for your help in advance.

What messages are you seeing from /var/log/maillog? Do you get any mail bounced back? If so what does sendmail report?

To test this you need to telnet from a remote location to port 25 of the server you want to test.

This is what it looks like:
--------------------------------------------------------------------
[darcy:07:13pm:m0rl0ck]> telnet m0rl0ck.ath.cx 25
Trying 66.181.96.21...
Connected to m0rl0ck.ath.cx.
Escape character is '^]'.
220 ///////////////////////// ESMTP
MAIL From:
503 5.0.0 Polite people say HELO first
helo
501 5.0.0 helo requires domain address
helo localhost
250 bunny.m0rl0ck.ath.cx Hello darcy.gwis.com [66.181.106.3], pleased to meet you
MAIL From: thepres@thebov.com
250 2.1.0 thepres@thebov.com... Sender ok
RCPT To: m0rl0ck@xxxxx.com
550 5.7.1 m0rl0ck@xxxxx.com... Relaying denied
---------------------------------------------------------------------

The above is me connecting to my mail server from my shell account with my isp.

1. after you get the sendmail shell enter a helo:
"helo localhost"
2. next type a:
MAIL From: user@domain.com
2. next type a nonlocal destinaton addy:
RCPT To: m0rl0ck@xxxxx.com

If you get relaying denied youre ok.

Heres a link or two on the subject:
http://www.linux-sec.net/Mail/openrelay.gwif.html
http://www.linux-sec.net/Mail/AntiSpam/

Open relay testing and also links to the monty python spam song

I checked the things as mentioned above, and I feel alot safer than before: Testing with the TELNET 25 option indeed shows relay denied.

Also the website mentioned is great! Thank you all for helping me out!

Others with the same questions: Please read above messages.

Thanks again,

Satriani