On Aug 16, 2011, at 10:09 PM, Michael C. Robinson wrote: > A curious question, shouldn't I be able to look up any IP that is > claiming to be a mail server via the DNS system?
In theory, yes. In practice, no. The only mail server records that have to be there are MX records, and those only say that the server there accepts email for the domain listed. A system administrator can set up any number of systems to send mail for their domain and doesn't have to list them at all in DNS. There are other mechanisms that are supposed to verify what servers send mail for a domain, such as SPF records. However, their implementation is spotty at best. Russell Johnson [email protected] _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
