DMC12

Hi,

On Friday afternoon one of our users send an email to 15 recipients. A short while later these recipients complained that they were receiving the same email over and over. A short while later these recipients mailboxes were either full or they had put a block on us. Our user then started to receive Underdeliverable Notifications.

This morning they had over 900,000 failure notification emails in their inbox. They were coming in faster than we could delete them, and around lunch time the server ran out of disk space and promptly fell over.

We've sorted the server out, but I was wondering what on earth could cause this behaviour. Our logs clearly show that the original message only went out once, and there has been no unusual outbound messages. We've received more emails in a day than we usually get in a month and as far as I am aware it's still going on, we've just disabled the users email address.

We use Exchange 2003 and Messagelabs.

Cheers

Steve.

Kieran_Burns

iTrader: (1)

Messagelabs? As in Mailsweep? Why didn't you just add a scenario to filter out undeliverables?

As to why they turned up in their droves in the recipients inbox..... got to be a send loop somewhere in that lot.... auto-forwarding?

Thinking about this... that user of yours (or someone else in the to: list) must've had a rule set to auto-reply to all recipients of an e-mail and included themselves in the reply list.... Instant Mail Meltdown.