-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 In message <[email protected]>, Alain Williams <[email protected]> writes
>Notes for discussion: > >* It stores sending-domain & IP address of sender. I've seen combining the IP address with sending (or receiving) domain work very badly indeed with ISP smarthosts (ie the machines that millions of customers use...) What happens is that the sending machine tries one email, which is then greylisted. The sending machine then marks the destination as unresponsive -- but eventually gets around to trying again. However, a different email is at the front of the queue, with a different customer domain and so that is also greylisted. The sending machine then marks the destination as unresponsive -- but eventually gets around to trying again. However, a different email is at the front of the queue... ... rinse and repeat until 4xx has been seen far too often, and all queued email is then marked undeliverable and returned to the senders. I don't understand why you feel that the property "will try again after a 4xx response" would not be associated solely with the IP address ?? If your concern is dynamic IP addresses (and you might do better to subscribe to a service that allows you to block those wholesale) then just age your database entries a bit more aggressively. Configuring Exim to have the retry behaviour mentioned above is left as an exercise for the reader [hint: install it!] -- albeit it might be helpful to tweak it to not to work quite that way (so as to deal with excitable greylist algebras). Note also that the bad effect discussed above is often hidden on Exim systems because an attempt will be made to deliver any new emails whatever the retry state and if one of them works then all the contents of the queue will be promptly retried... but when queues build up then nothing gets retried for hours and then aggressive aging of greylist entries will seriously hurt you! ... recipients can of course improve matters considerably by not applying greylisting to the major sources of incoming email (ie: all the reputable local ISPs). - -- richard Richard Clayton Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety. Benjamin Franklin 11 Nov 1755 -----BEGIN PGP SIGNATURE----- Version: PGPsdk version 1.7.1 iQA/AwUBS2HBipoAxkTY1oPiEQJyeQCdEr/Pb1x4acE3GXdrtWo5SANCxKEAn3ta O1xtwQQgAzF+yV6wzvmc79eU =6O9g -----END PGP SIGNATURE----- -- ## List details at http://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
