clarify documentation to note clearly that MXes must perform DNS name resolution, for whitelist_from_rcvd to work
clarify documentation to note clearly that MXes must perform DNS name resolution, for whitelist_from_rcvd to work

git-svn-id: e9fe9b84e32fc5e57b7d09c40cd78b14ea28ed71@560957 13f79535-47bb-0310-9956-ffa450edef68

apache/spamassassin,apache/spamassassin,apache/spamassassin,apache/spamassassin,apache/spamassassin