Re: Handling SMTP errors

"Todd A. Jacobs" <[email protected]> writes:

> Charter is a rotten ISP, but they probably typify the industry. One of
> Charter's lame policies is that they refuse to process bounces for a
> number of domains such as gmail, presumably in a non-RFC compliant way
> to prevent joe jobs.
>
> Anyway, I get a lot of transactions like this:
>
>     Jun  1 10:53:17 penguin postfix/smtp[21794]: E4CF237CA9:
>     to=<[email protected]>, relay=smtp.charter.net[209.225.8.224]:25,
>     delay=0.94, delays=0.05/0.07/0.66/0.16, dsn=5.0.0, status=bounced
>     (host smtp.charter.net[209.225.8.224] said: 550 relaying mail to
>     gmail.com is not allowed (in reply to RCPT TO command))
>
> when TMDA attempts to send its challenge message. So, while TMDA is
> obviously working as designed, it raises a few questions:
>
>     1. Should challenges be bounces, or new messages? Bounces help
>        prevent joe jobs, but obviously run afoul of relay restrictions.
>
>     2. If they remain bounces, how should undeliverable errors be
>        handled? Currently, messages remain in the pending queue, but
>        perhaps other configurable actions (hold, discard, or deliver to
>        known-spam folder) might be more appropriate.
>
> The current flaw isn't in TMDA, but I think the question of how TMDA can
> handle ISP ignorance is a good one to discuss.

Most of TMDA's behavior in this area is governed by RFC 3834

http://www.faqs.org/rfcs/rfc3834.html