Sender Policy Framework (SPF)

All of us hate spam and many wonder what can be done to fight this menace. Here's one thing eveybody can and should do that will make a difference - ensure that your DNS server has a so called SPF record. An SPF record is a resource record (RR) of the type TXT that looks like this (this is just an example):

v=spf1 ip4:192.168.1.0/24 ip4:192.168.2.0/24 ~all

All SPF-compliant SMTP servers will try to obtain the SPF record for the domain that is trying to send mail, which tells the SMTP server that mail from the domain in question may only be sent from the specified addresses. If a spammer tries to forge a domain name, their IP address will not match those listed in the domain owner's DNS.

If you would like to read more about SPF, here's the link that will answer most questions:

http://spf.pobox.com/faq.html

You can check if your current DNS server has an SPF record here (it's at the bottom of the page):

http://www.dnsreport.com

Many existing domains, such as hotmail.com, are configured with one or more SPF records.

Having an SPF record in your DNS will not reduce the amount of spam *you* receive, but rather prevents someone else sending spam using your domain name. It's reciprocal, though - if your SMTP server is SPF-aware, you won't receive spam mail from hotmail (unless it's been sent directly from a hotmail server).

J.D.

 

Keep in mind that the SPF PO Box website will give you quotes and if you are on a Windows server, you do not need those quotes.

A good site to check to see if the SPF record is correct: http://www.dnsstuff.com/pages/spf.htm and one more wizard: http://www.anti-spamtools.org/SenderIDEmailPolicyTool/Default.aspx

 

Great information guys. Thanks!