>Yeah. My favorite recent braindamage was a site that sent back errors
>by simply reflecting the message back to the "to" address. the only
>headers changed were the addition of Received lines and a new
>Message-ID -- so I couldn't even trap the loop based on duplicate
>sendings. This started a really gnarly mail loop on a list before I
>tracked it down, and I'm still unsure how to protect my system from
>it other than banning those domains (FWIW, it's an aged version of a
>microsoft mail gateway...).
Hmm. If it didn't change any existing headers except Message-ID: then
you can detect it from any headers written by your list software, such
as for example Sender:.
-Mitch
