We have our own Exchange 2003 mail server running on Windows Server 2003 and have never configured SPF records. Our email addresses are @domain1.com but our mail server is mail.domain2.com in the MX record for domain2.com. We also use Trend Micro for inbound email filtering only, so the MX for domain1.com is Trend's inbound. Domain2 is hosted by GoDaddy and domain1 by tkcars. Our ISP is Windstream. If I need to add an SPF, do I need to do it for the domain1 domain or domain2 or both? What should it look like? mail.domain2.com has one public IP address but the A record for domain2 is another IP address, so I presume it would look like: "v=spf1 a:mail.domain2.com -all". Do I just add this for domain2 on GoDaddy's console or do I need Windstream to also add it. Perhaps I've configured it wrong, but I have Windstream's DNS servers as the forwarders on our internal DNS for domain1 and domain2 (since they're under the same DNS server), not GoDaddy or tkcars.