I don't know much about mail servers, but let's say I had a sales@example.com address, and that it got a lot of spam.

Could I create a custom bounce message for emails sent to that address?

One reason, I'm thinking, would be to rename the address to something less spam-susceptible, and then have a bounce message containing the real address people should use.

Any thoughts? Thanks in advance!

  • 1
    Which mail server are you using? – Massimo Sep 2 '09 at 20:27
  • Not actually using anything, just a hypothetical. – John Bubriski Sep 2 '09 at 20:29
  • 1
    The answer depends heavily on the mailserver you're using. – Massimo Sep 2 '09 at 20:37

You could. However, think about what will happen when a spammer sends a message to sales@example.com with a forged (but deliverable) envelope From address. You'll send your bounce to that address. Whoever owns it probably won't appreciate that very much. Backscatter is a big problem. You could very easily find yourself blacklisted.

  • Interesting. I never thought of that as an issue! Excellent point! – John Bubriski Sep 2 '09 at 21:07

What would keep the spammers from using the real address, since you'll be advertising it to them in your bounce message? An email can't determine a real user from a spammer, bot, etc.

  • I understand that, but how many spammers read their bounce messages? Or do most of them automate their software to READ bounce messages and spam addresses found within? – John Bubriski Sep 2 '09 at 21:06
  • IDK, but I wouldn't send them a valid email address. It might be better advised to invest in a good anti-spam solution. Email addresses like sales@, support@, help@, info@, etc., etc. are always going to be prime targets for spam. – joeqwerty Sep 2 '09 at 21:43

I don't think this is targeting randomized spams which would be subject to backscatter. I think the idea is to bounce to mainslease operations, who need to find spam-friendly ISPs or spam ESPs. They may use forged "reply-to" headers, but only identifying spamvictims and the like. So the idea is to inform the upstream spam host and ideally inform their upstream mail host that their netblock is being blocked for spam.

But the second problem is, the bounce is going to default to the spammer's email address, rather than the spam host. It would be nice to get around this and say something like, "5.1.8 - Communications from netblock 192.168.1 1/24 blocked due to spam."

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