We are seeing a lot of mail sitting in queues for bogus MX's that resolve to either RFC1918 space or to just bogus IP's in general. Before we implement, what exactly happens when a message in queue hits this list? Does an NDR get returned to the sender address or is the mail silently discarded? Since this is mostly to prevent some spam/virus backscatter in some cases, is it possible to silently discard?
Config parts in question: BAD_MX_LIST = <; 0.0.0.0/8 ; 127.0.0.0/8 ; 10.0.0.0/8 ; 172.16.0.0/12 ; \ 192.168.0.0/16 ; 224.0.0.0/3 ; 169.254.0.0/16; \ !2000::/3 smtp_routed: driver = dnslookup domains = !+local_domains transport = remote_smtp ignore_target_hosts = BAD_MX_LIST -- Robert Blayzor INOC, LLC [email protected] http://www.inoc.net/~rblayzor/ -- ## 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/
