I had a very interesting conversation with a sysadmin who is in charge of mail server whose emails our Spamdyke servers are rejecting because their PTR has no corresponding A record (reject-unresolvable-rdns in spamdyke.conf).
The sending server runs MS Exchange 2007, and apparently when they add an A record for their PTR, their webmail (whether accessed externally or internally) stops working. Does anybody have any experience of Exchange 2007? Does this make any sense? It doesn't to me. But I don't know enough about how Exchange works and how its webmail thing works either to make any real comment. My only guess is that it has something to do with the exchange server using a local private IP for the webmail server internally, and when this is effectively changed to a public IP it all falls down? I don't know why they can't just change the external DNS and leave the internal stuff alone, unless the Exchange server actually runs the external DNS too? Argh. It makes my head hurt just thinking about it. Obviously we can whitelist them - problem solved - but not everybody will do that for them and they are going to face some serious problems before long as more and more ISPs and mail servers come to reject on an unresolvable RDNS. And if it is a generic problem with Exchange then that's going to be a bigger problem for us and others. Faris. _______________________________________________ spamdyke-users mailing list spamdyke-users@spamdyke.org http://www.spamdyke.org/mailman/listinfo/spamdyke-users
