Blocking outgoing email

[#1]

Is it possible to block outgoing emails in a certain domain range. I have an infected computer behind my firewall that is sending spam, but I cannot figure out which computer it is because it is a student owned computer and I have alot of them to check and that takes time. I know the approximate times it sends, but cannot find out what unit it is because we have no fortianylizer to archive the data, all I can see is that it is leaving in my email content archive. I cannot find anything in the protection profile, so I am stumped. Thanks for any help. I have a Fortigate-60 3.00,build8845,080730 Here is part of my log that I get, I can only see the last 64 transactions from last night. 2009-04-21 09:04:11 email address@painkillerdetox.com email address@bb-sportnahrung.de support your sexuality 2009-04-21 09:04:12 emailaddress@thing.net emailaddress@provincia.so.it hoist your lover night event

[rwpatterson]

Block SMTP from the student IP range outward. Actually it should be blocked for all but corporate email servers...

[red_adair]

Did you think about " log allowed traffic" for a tcp/25 (smtp) rule and log this to a standard Syslog-server ? This should reveal at least the senders IP. You can also go to " AntiSpam" and write your own rule. For example " emailadress" -> Wildcard (Regex) and have your domain marked as clear. Than create a PProfile for outgoing SMTP and apply this to AntiSpam Section within the PProfile. Action for SPAM would be " discard" . Outgoing SPAM will be discarded. Trigger for being SPAM will be if an email is not having a certain domain-name. -R.

[#4]

Thanks for the help, I created a new profile that blocked the students from SMTP and this has stopped the spam, I am now trying to log all violations, but have had limited success so far. I may try the opposite way where I let the info go and log for a couple of hours, but I also need to get my syslog server receiving more info, only some events are being passed so far.