All the Perl that's Practical to Extract and Report

MAILER-DAEMON

barbie on 2003-07-15T16:58:55

Having suffered enough with bounce emails to my home account (over 200 this morning), I have now decided to automate some bounces of my own.

Once upon a time I would email the ISPs directly and explain the pointlessness of sending a bounce to spam, as virtually all spam contains a spoofed email address. This worked for a few, but seeing as I'm now getting hundreds of these I don't have the time to sit and write to ignorant ISPs [1].

So, I've written a little script using Net::POP3 to lookup the messages and spot any that might be bounces from emails. The script will then send a one off bounce to that address for each bogus mail account they reply to. The Reply-To is set to spamtrap@missbarbell.co.uk [2], so they automatically get blacklisted if they send a reply. We shall over the coming weeks whether this has any effect.

Once I've finished tweaking I may post the code somewhere for others to use or offer advice/patches for enhancements. Perhaps the scripts directory in CPAN might be an idea.

[1] Okay so they may not all be ignorant, but anyone not ignoring spam in the first place can't be all that bright. [2] Mailing to this account would be a bad idea, but you knew that right ;)

Spam bounces

vsergu on 2003-07-15T18:19:57

If I'm sending mail, I want to know if it's not delivered. That's not always going to happen, I realize, but there are ways that mail servers are supposed to behave to make it more likely.

Servers that send bounces in response to (what may be) spam are far better than servers that erroneously decide a message is spam and summarily blackhole it without a bounce or any indication to the sender (or recipient, for that matter) that something's wrong. Spam filtering is not perfect -- some systems are very far from it -- and making e-mail less reliable than it already is doesn't help.

Now, if you're talking about virus scanners that send bounces, even when the virus is known to be one that forges the return address, I agree with you that they're stupid.

Re:Spam bounces

barbie on 2003-07-15T21:58:41

They are sending responses to spam. No ifs or buts, it's spam. They even include the spam to prove it's spam. Some even reply with a SpamAssassin header style ****SPAM**** just to be sure.

The problem is more that most of the ISPs that are sending these bounces haven't been configured to check for spam mail. I **KNOW** spam filtering isn't perfect, I work alongside Matts at MessageLabs, although Matt's spam teams efforts are about as near perfect as you can get at the moment.

Maybe you are lucky enough not have over 200 of these messages a day, my main domain isn't so lucky.