At 9:09 AM +0100 1/9/07, Jorge Chamorro imposed structure on a
stream of electrons, yielding:
Hello,
Lately I started to receive this kind of messages from certain smtp
transactions:
Failed to deliver your message to [EMAIL PROTECTED]:
SMTP: Address rejected by host
Host 'mail.somedomain.com' says:
450 <[EMAIL PROTECTED]>: Recipient address rejected: Greylisted, see
http://isg.ee.ethz.ch/tools/postgrey/help/eurocarne.com.html
It seems (after reading the whitepaper in the above link) to be a matter of
re-sending it in a few minutes (?).
Therefore, is it enough to re-configure the smtp settings so as to retry
several times over a longer period of time ?
It should be, but SIMS has some difficulties with some greylisting
implementations because it does not understand the specific 4xx
response code used as being a temporary failure. If memory serves me,
the last dev version of SIMS (1.8b9d14) should not have a problem
with 450 responses to RCPT.
It is not robust (and never has been) to have an SMTP server retry
messages that get 4xx 'temp fail' responses more frequently than
every 5 minutes, less frequently than every 30 minutes, or for less
than 12 hours total.
Anyone has experienced this, and knows a workaround ?
Greylisting is designed to allow normally behaving mail servers to
work normally after an initial delay. The idea is that real mail
servers (in contrast with the trojan spamware sending most spam these
days) have requeue/retry strategies that will have the same message
coming back again in a fairly short time (5-30 minutes) from the same
IP address if the sending system is legitimate, and even for the
quasi-legit spammers who use their own real mail systems on static
IP's, a forced retry adds a chance for external blacklists to notice
the spammer. For many greylisting systems, the delay only has to
happen for one message as long as you are exchanging mail with the
site using greylisting relatively often. It works very well, except
with oddball mail systems that don't retry in the range of
frequencies and lifetimes as the bulk of mail systems.
--
Bill Cole
[EMAIL PROTECTED]
#############################################################
This message is sent to you because you are subscribed to
the mailing list <[email protected]>.
To unsubscribe, E-mail to: <[EMAIL PROTECTED]>
To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]>
To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]>
Send administrative queries to <[EMAIL PROTECTED]>
