How Fetchmail made me a spammer

Dag-Erling Smørgrav des at des.no
Thu Jan 14 12:07:41 UTC 2010


Benjamin Lutz <mail at maxlor.com> writes:
> 2) Fetchmail downloads that 20MB email from the public POP3 server.
> 3) Fetchmail tries to pass the email to the local postfix server.
> 4) Postfix refuses the email with a permanent 552 error because
>    it's larger than 10MB.
> 5) Fetchmail generates and sends a rejection notice, but does not
>    delete the 20MB Email from the POP3 server because the
>    "softbounce" option is still the default.
> 6) Fetchmail sleeps 60 seconds.
> 7) Continue at step 2).
> [...]
> - Fetchmail's defaults are dangerous. The softbounce option, which is the
>   default (the manpage claims it'll be disabled by default with the next
>   version,) can generate large amounts of spam.

None of this would have happened if you were using IMAP instead of POP.
Unlike POP, IMAP a) provides a way to mark a message as "processed"
without deleting it and b) does not renumber messages or reuse message
numbers.

DES
-- 
Dag-Erling Smørgrav - des at des.no


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