On Wed, Jun 6, 2012 at 4:45 PM, Balachandran Sivakumar
<benignbala at gmail.com> wrote:
? ? Let me give a brief explanation of how it works.You publish SPF
records for your domain. So, in your DNS, you add entries like
mydomain ? ? ? ?IN ? ? ?TXT ? ? "v=spf1 +mx -all"
When a remote server receives a mail, it does a TXT look up, sees that
only those machines with an MX entry can send record, and so sees if
the sending machine has an MX entry and accepts it. Otherwise, it can
reject it.