This is too funny not to post here (warning: only funny for the technically inclined):
[17:58] beezle:~ % dig mx masn.com ; <<>> DiG 9.2.2 <<>> mx masn.com [...intermediate output snipped...] ;; QUESTION SECTION: ;masn.com. IN MX ;; ;; ANSWER SECTION: masn.com. 86326 IN MX 10 10.0.0.2. [...rest snipped...]
…and yes, this is resolved from the greater internet (i.e., not from behind a firewall or anything like that).