:~$ dig ebay.com mx ; <<>> DiG 9.7.2-P2 <<>> ebay.com mx ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16443 ;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION: ;ebay.com. IN MX ;; ANSWER SECTION: ebay.com. 3311 IN MX 10 lore.ebay.com. ebay.com. 3311 IN MX 10 data.ebay.com. ebay.com. 3311 IN MX 10 gort.ebay.com. On Tue, Aug 16, 2011 at 11:09 PM, Michael C. Robinson < plu...@robinson-west.com> wrote: > Ebay, St Helens Community Federal Credit Union, ... > > Question I have, why aren't these email sources reverse resolvable? > > *:~$ dig ebay.com mx* > > ; <<>> DiG 9.7.2-P2 <<>> ebay.com mx > ;; global options: +cmd > ;; Got answer: > ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16443 > ;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 0 > > ;; QUESTION SECTION: > ;ebay.com. IN MX > > ;; ANSWER SECTION: > *ebay.com. 3311 IN MX 10 lore.ebay.com.* > *ebay.com. 3311 IN MX 10 data.ebay.com.* > *ebay.com. 3311 IN MX 10 gort.ebay.com.* > *:~$ dig 10 lore.ebay.com.* ; <<>> DiG 9.7.2-P2 <<>> 10 lore.ebay.com. ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 14750 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;10. IN A *;; ANSWER SECTION:* *10. 0 IN A 208.68.143.50* ;; Query time: 19 msec ;; SERVER: 68.87.69.150#53(68.87.69.150) ;; WHEN: Wed Aug 17 02:04:54 2011 ;; MSG SIZE rcvd: 36 Also, what about checking SPF records? This is a common tactic of many a spam filter. http://www.mxtoolbox.com/spf.aspx _______________________________________________ PLUG mailing list PLUG@lists.pdxlinux.org http://lists.pdxlinux.org/mailman/listinfo/plug
