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Looping E-mails Beat The Net Down

Posted by CmdrTaco on from the i-want-my-smtp dept.

Staili writes "Singapore-based women's magazine caused problems when it forwarded its mails to a large list of recipients, mainly mailing lists. In addition to security@suse.com, some help and subscribe lists were included; the type of addresses that tend to send out an automatic reply confirming receipt. And the loop was ready." I'm sure anyone who's messed with mail enough has accidentally created a loop or two in their day, but this is really slimey.

1 of 183 comments (clear)

  1. Re:Why was the header stripped... by Corgha · · Score: 5, Informative

    Somehow, few people seem to be able to get the autoresponder/autoforwarder thing right, despite the fact that it doesn't seem that hard and has been done correctly before. (Then again, there seems to be a dearth of good systems programmers around these days; I'm becoming increasingly cynical about such things.) Every day, I get auto-replies to MAILER-DAEMON's bounce messages, and every once in a while, some b0rken forwarder creates a mail loop. Unfortunately, when I try to tell the people responsible why what they are doing is a bad idea, they're usually not interested in hearing about the danger of mail loops.

    Here are some things I've come up with over the years:
    1) Never, ever auto-reply to MAILER-DAEMON or Postmaster (procmail has good regex macros for this -- use them or copy them).

    2) Preserve the headers of messages you forward.

    3) Set an X-Loop header and check for it (or *any* X-Loop header if you want to be paranoid).

    4) Don't autoreply to the same address twice during [definable time period].

    Those things just seem like common sense to me. Maybe someone else here knows more about the subject than I do. There has to be a HOWTO somewhere.