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Re: backscatter (was Re: [EMAIL PROTECTED] bounces?) Charles Gregory Fri Jun 26 08:00:20 2009

On Thu, 25 Jun 2009, Arvid Picciani wrote:
 I still welcome suggestions for handling the few remaining cases where my
 procmail chokes on a mailbox limit. Probably more of a PM question than an
 SA question, but seeing how the cause for concern is backscatter from
 'full mailbox' DSN's I'm figuring the answer is here, if anywhere....
1)  your MTA bounces, becouse your users mailboxes are full.

Of the two questions, this one is closest, but it's not the MTA that generates the bounce. The MTA has handed off the message for delivery to individual recipients after accepting the DATA. Procmail encounters the full mailbox and signals the MTA.

My MTA checks for a mailboxes that are *already* over quota while dealing with individual 'RCPT_TO' commands. The problem comes after I receive DATA and know the size of the mail. At this point the only actions my MTA can take are for ALL recipients. I can't reject mail just for *one* recipient with a (nearly) full mailbox. The only 'workaround' for this would be to have my MTA enforce individual recipients by returning a 4xx code for second and subsequent recipients. Mind you, this might actually help with some spam, but it would also add to bandwidth for ALL legitimate mail with multiple recipients, forcing transmission of the data/body for each one.

2) You're receiving backscatter and you get "mailbox full" DSNs
I find it impossible to parse DSNs. There is no standard and its supposed to be human readable.

This wasn't my question, but I have a 'fairly good' answer for it:
I do a body check for a quoted From line that has the wrong 'name' in front of my address.... Eg. "From: Bob Kenny <[EMAIL PROTECTED]>...

- Charles