Sender Policy Framework
SPF and Sender ID
Many of the larger e-mail providers use SPF, among these are Hotmail, GMail and Yahoo! Mail.
SPF is a technology which, through special DNS lookups, makes it possible for the recipient to see which e-mail servers are allowed to send e-mails for the specific sender.
Our SPF data are available as both TXT and SPF DNS records
Make a query on mxtoolbox.com
Besides SPF we also support Sender ID validation. Sender ID is a technology very much alike SPF, but validates another aspect of the messages. With Sender id, the sender address, the one we allow you to specify. Thus, this is not something we can control, but we do however monitor your sender address and will warn you inside the system if there appears to be a problem.
Sender ID is primarily used in Microsoft server environments. Hotmail and most corporate mail servers employs this kind of checking.