Program to monitor e-mail sent from my LAN?

AlucardZero · 07-10-2008, 07:49 AM

Hello,

My ISP has told me that it detected spam coming from my connection. I find this rather unlikely*, but I'd like to check. My router is a Debian box; what is/are some program(s) that will let me monitor mail sent from all boxes on the LAN to all destinations?

* the router is a Linux box, and the clients are a Vista w/ AV and firewall, an XP VM not used for internet, and two Macs.

unixfool · 07-10-2008, 07:56 AM

tcpdump can do that.

simonapnic · 07-10-2008, 02:48 PM

You might want to run a packet sniffer, which can sniff SMTP traffic and identify the objects (recipient, message..). I suggest Wireshark.
Check the mail queue as well, it might have some unsent data if the mails were sent from your connection.
What SMTP daemon are you using ? Exim ? Sendmail ?

AlucardZero · 07-10-2008, 05:35 PM

postfix, but LAN clients don't send mail through the router. The only mail that's been sent from the Linux router in the past two weeks are the daily logwatches.

I don't have a GUI on this machine, and it's remote at the moment. I will try tcpdump and see if wireshark has a non-GUI mode.