[Full-Disclosure] Block notification / bounce mails (as in DDOS)

[Jos Osborne]

Had a similar situation here - didn't know there was a problem till the exchange server crashed because the dear user didn't think to tell me she had about 3500+ spam mails in her deleted items...

Fortunately, all the e-mails came from the same person, so I was able to tell Exchange Server to simply not accept any e-mails from that address.
Don't know about if they were all coming from different places though. It might be possible to filter out all mails with "Undeliverable Mail" in the header, but the overheads might be crippling.

Jos