SPF, Sender Policy Framework thats what. Its a TXT record you can apply to your DNS zone to allow receiving mail servers to determine whether your email domain is being impersonated to send spam (UCE). Why is this important? Well if you have more than 1 SMTP sending server then your IP address ranges may be different. This means that some of your email may be rejected as spam at servers like Hotmail and never reach the recipients mailbox (even the junk mail folder). Once added, mail servers can check the SPF record to confirm your email is valid and hopefully your email won’t be rejected.
So what does an SPF record look like ? Well here’s an example;
v=spf1 ip4:62.21.98.128/24 a mx include:spf.myispmail.net ?all
But working it out is a chore, so go to an easy to use online configurator here http://old.openspf.org/wizard.html
