[Mimedefang] greylisting returning 451
Kevin A. McGrail
kmcgrail at pccc.com
Fri Sep 22 07:21:17 EDT 2006
This is one of the problems with greylisting. Essentially, a 4XX error is a
temporary failure and a 5XX is a permanent failure. There is most likely
nothing wrong with your filter but the brain-dead server on the other end
isn't trying to redeliver.
Now, the good news is that ratware generally can't tell the difference
between 4XX and 5XX so it just doesn't try again. This is why greylisting
is effective.
Another other problem with greylisting is that some places do not try a
redelivery for hours and sometimes days. Are you sure this is legitimate
mail that is never being redelivered and have you waited a day or two for
redelivery attempts?
Regards,
KAM
> My greylisting package is returning a 451 and some sites are interpreting
> this as a permanent error. What should I be returning? A 430? How is this
> done in check_recipient?
More information about the MIMEDefang
mailing list