Mail relay to customer server

[kilburn]

ispcomm Wrote:The traffic volume is OK until you have tens of thousands emails per day on a that particular domain. Postfix checks the recipient in a parallel session before accepting it to the sender so you still get the bonus of not accepting undeliverable and forged recipient mail.

My customers using this service receive an avg of ~10k delivery attempts to unexistant accounts each day. As currently greylisting is done AFTER validating the recipient address (good thing if the machine has this info because it avoids filling the greylisting database with known-to-be-rejected delivery attemps), most of this ~10k attempts would generate a verify request, and the Exchange server of our customers will probably die (You know exchange is a really big piece of shit, don't you?)...

If you reconfigure postfix to greylist before validating recipients the customer server's won't die, but your postgrey database would grow several times bigger and the waste of resources will be noticeable.

IMHO this is a "setup/admin cost" vs "bare resources cost" issue.