Hi, I have a problem where a user sets a vacation message which autorespond to an incoming email. In some situations, the sender's mailbox is full when the auto message reaches him/her, or so far mostly a spam with a spoofed email address that's already invalid.
What happens next I believe is a mail loop. The "sender" auto replies with a "cannot deliver, mailbox is full or user is invalid". Then my user's vacation message respond to that, and so they pingpong until even my user gets a full inbox which then seems to generate two responses, one for vacation and one for mailbox full. Things go south rapidly from there as each bounce causes the email to grow bigger and bigger, making spamassasin/clamav spend more and more time processing them, as well as exim requeuing them for another attempted delivery. Based on what I've found online, I already set the option in exim to check for received_headers_max. Unfortunately, in this case, it seems that the other server strips all headers so this limit is never hit. The only thing I can see from looking at the bouncing emails that might be a clue is the returned mail gets the whole email subject appended with a newline char included. However, I can't figure out how to get exim to drop any emails with more than 1 \n in the subject or any \n. Since I don't think in the first place there should be any newline chars in a normal email subject. Any advise on how I can achieve this or is there a better way to catch this sort of situation? -- ## List details at http://lists.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
