This article covers How to Manually Create SPF DNS records on your server through the DNS Management Console.
Windows Server 2003:
Open up your Start Menu and navigate to “Administrative Tools -> DNS”.
Expand the ServerName (eg: sv2400), then “Forward Lookup Zones”. Click on the domain you wish to edit, then right-click in the right-hand window pane and select “Other New Records…”
Scroll down to “Text” and select “Create New Record”
Leave the “Record Name” blank, and enter the following in the “Text:” field:
Repeat steps 4-8 for each domain you wish to add SPF records to.
There are a number of options that can be specified in the SPF record, for example, adding an IP address that does not correspond to the Host A or MX record of your domain. We recommend contacting Technical Support with such requests as DNS records are critical to your email and other publicly accessed services.
Note: DNS record changes will take about 24-48 hours to propagate throughout the internet.