Slashdot Mirror

← Back to Stories (view on slashdot.org)

Some Anti-Spam Vendors Blocking and Slowing Gmail

Posted by ScuttleMonkey on from the need-something-more-dire-than-can-spam dept.

fiorenza writes "Google's Gmail (and corporate mail) are being throttled and sometimes blocked by some anti-spam services, including MessageLabs and Antigen. Ars Technica reports that the blocking is a result of the Google CAPTCHA crack, which has allowed a deluge of spam from Gmail's clusters. Most users won't get blocked mail, but Ars confirmed with MessageLabs that Gmail delivery delays are to be expected."

1 of 163 comments (clear)

  1. Re:Gmail and others blocking legit domains, so hey by gnuman99 · · Score: 4, Informative

    Here's what happens. On SMTP level. << is for what server sends. Rest is what is sent to server.

    << This is your great SMTP server. Yo!
    << 220 super.server.net ESMTP
    HELO srv.my_super_subnet.server.net
    << 250 srv.my_super_subnet.server.net
    MAIL FROM: <handle@server.net>
    << 250 2.1.0 Ok
    RCPT TO: <handle2@server.net>
    << 250 2.1.5 Ok
    DATA
    << End data with <CR><LF>.<CR><LF>
    Subject: Yo
    From: Bob Superman <handle@server.net>
    To: My Buddy <handle2@server.net>

    Want some viagra?

    .
    << 554 5.7.1 Rejected, id=sdsada - SPAM
    QUIT
    << 221 2.0.0 Bye

    See?? No backscatter. The pre-queue filter runs *before* the message is accepted after the . is on the new line indicated end of message.

    What happens now is they get,

    << 250 2.6.0 Ok, id=fsffs FROM blah Ok: queued as foo

    or similar response. Then the filter runs and junks the mail! *That* runs email. I send out email, and it get junked. It gets delivered 50% of the time because some wise guy runs some new magic filter - no spam gets through, and 50% real messages get binned. Then people that should get mail complain that they never get mail (and not just from me).

    If you reply to message from a post queue filter you get backscatter. This is wrong way of doing things. If you reject mail in pre-queue, there is NO backscatter.

    The *only* reason to run after queue and drop silently is for mail marked as Bulk, like mailing list software marks mail as Bulk precedence. Any other mail should be treated as a *no* mail lost priority. Otherwise we may just abandon SMTP altogether.