When I set up an autoresponder in my .sieve file, I specify ":days n", where "n" is the minimum number of days between allowing an autoresponse to be sent to the same address.
This isn't fool proof though. It would fail if the other side of the loop didn't have a similar defense, and also sent each email response from a different address.
This isn't fool proof though. It would fail if the other side of the loop didn't have a similar defense, and also sent each email response from a different address.