I need help with something I do not really understand. I am getting over a thousand delivery errors within a few minutes because some spammer is using one of my email address as the "reply to" address on the junk they are sending out. I understand that the SPF record is supposed to help prevent this from happening, but I can't seem to figure out how to set this up properly.
Let me first describe the environment I have:
Four Dell Windows2003 servers:
Exchange2003 Server ES01 xx.xx.xx.157
Domain Controller Server DC01 xx.xx.xx.190
Web Server WS01 xx.xx.xx.131 - 150
Web Server WS02 xx.xx.xx.156
I am hosting several domain names on the web servers and accept email for all of them on the Exchange server.
My understanding is that I should add the SPF record to the DNS server on DC01. (Is that a correct assumption?)
How do I include all the domains in the SPF record? (Or do I create multiple records for each domain?)
Initially, I had just:
v=spf1 mx ~all
in the DNS of the primary domain on DC01. I have also tried other variations:
v=spf1 mx a:ES01 include:domain1.com ~all
v=spf1 mx ptr mx:smtp.domain1.com ip4:220.127.116.11 mx:domain2.com ~all
None seem to be working based on testing at:
Can anyone walk me through what this record (or records) need to look like so that I can verify it works via the microsoft test site listed above?