On Tue, 24 Sep 2002 17:34:09 MDT, Ben Parker <[log in to unmask]> said: > The theory of SMTP error codes (see RFC821) requires this of any/all mail > transfer agent programs, including LSMTP. 5xx errors are classified as > 'permanent' meaning retry will most likely not succeed. The descriptive > text after the 554 may offer slightly more of a clue. Yes - but RFC821 *also* says that a 4xx error should be returned for conditions that will probably succeed if retried later, without any user intervention. So "system load exceeded" should cause a 4xx reply, because there's a good chance that if the sender system retries in 30 mins, the load will have dropped. On the other hand, "user over quota" is specifically mentioned as needing a 5xx code - although it's *possible* that the recipient will be under quota at the next retry, it won't happen unless a human intervenes and cleans out some mail. (I have seen systems that *properly* return '4xx User Unknown' errors if they were unable to get a read lock on a user database and waiting is impractical because you're not supposed to delay the '250 OK' *too* long... Given that Hotmail usually reports *other* 5xx errors with a fairly good explanatory text like "over quota" or "deactivated user" and so on, the current spate of '5xx Transaction Failed' sounds like plain crack-induced bogosity - especially in conjunction with all the connection reset and refused errors I'm seeing. Today's Sendmail tip: If you're running 8.12 or later, you can use the "queue groups" feature to push all the outbound Hotmail traffic into its own queue directory, so it doesn't clog things up for functional systems...