On 31/05/11 02:22, Todd Lyons wrote: > This is from the NANOG list. Is anybody else attempting to prevent > backscatter by blocking emails from customers using smtp auth that the > sender is <> or postmaster (and recipient is not local)? This is not > something I have ever considered, looking to see if anybody else has.
Not quite along the same vein, but close .. it's on a gateway for a business network. I have one customer who used to get themselves blocked constantly with backscatter. They would complain to me, I would explain why they needed to change what they do, they would say they couldn't do it because of X,Y and Z. So I did it for them and they haven't noticed yet. They would send out MSexchange vaction replies to any external address that sent to them any time the person left the office, including outside work hours. I do not have control over this exchange server and it has a few other bad habits configured into it which cause numerous other bounces to happen. The solution was to block all null senders with matching fingerprints from inside the network. I currently accept but freeze them. After 72 hours, I wipe them from the queue, just in case there's a legitimate one and I happen to look at the queue in that time. Haven't found one legit one yet. Since doing this, they haven't been blocked once, and they haven't received one complaint. They haven't lost any business, and the world hasn't fallen off it's tilt. It seems X, Y and Z were not all that relevant after all. I freeze anything that comes from inside the network with a subject that says "Out of Office AutoReply" in whole or in part. I was blocking all <> senders but these turned out to be quite benign compared to OOR. -- ## List details at https://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/
