You might want to look at Net :: Server :: Mail in perl (had to space weird to keep from smilies!). It has all the functionality to listen on a socket and handle basic transactions, however there is some writing that you'd have to do.
regarding people's computers sending spam. that is a shame, and the new mail server will kill all their disk space very soon.
maybe that's a good thing, they will notice that something is wrong with their computer.
Err, you're planning to hack computers belonging to innocent people and fill up hard disks ??
If you're thinking about sending mail back to the source IP address think again, just because an MTA sends mail out doesn't mean it'll receive mail, infact I've never seen a compromised machine that would even respond to incoming SMTP traffic.
█ Dan Kitchen | Technical Director | Razorblue
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