This article will help you set up SPF records in order to improve email delivery and will also include links to help you understand SPF technology.

Some SPF Background

Domains use public records (DNS) to direct requests for different services (web, email, etc.) to the machines that perform those services. All domains already publish email (MX) records to tell the world what machines receive mail for the domain.

SPF works by domains publishing "reverse MX" records to tell the world what machines send mail from the domain. When receiving a message from a domain, the recipient can check those records to make sure mail is coming from where it should be coming from.

With SPF, those "reverse MX" records are easy to publish: one line in DNS is all it takes.

SPF Can Help Deliverability

More and more ISPs are requiring SPF records to be published under your domain name in order accept your emails.

Setting up an SPF Record

1) Remember, SPF records must be set up under the domain you use for your FROM address (the email address you send emails from). This means you must have access to the domain's DNS record. Contact your website host to see what kind of access they offer.

2) If you already have SPF records published under your domain name, simply add your Email System account Private IP address to the record. You will find it on all paid accounts, at the bottom of the ACCOUNT INFO page.

Important: Do not configure your SPF record using the IP address found on trial accounts. This IP address is shared by all trial account users. Instead, upgrade your account to receive a Private IP address, and then configure your SPF record.

3) After publishing, please contact us and we will also configure records on your Email System account.

4) If you do not already have SPF records published, please use the following format and have your DNS manager publish them under your domain.

yourdomain.com. IN TXT "v=spf1 mx ip4:Email System PRIVATE IP ADDRESS ip4:YOUR MAIL SERVER IP ADDRESS -all"

As a general rule, you will want to include any IP addresses you want associated with sending email from your domain. After publishing, please contact us and we will also configure records on your Email System account.

While You're At It: Setup SenderID

We also recommend you add a second entry for improving delivery to Hotmail, called a Sender ID record. This entry should include the exact IP addresses as the spf record, but contain slightly different parameters.

yourdomain.com. IN TXT "v=spf2.0/pra mx ip4:Email System PRIVATE IP ADDRESS ip4:YOUR MAIL SERVER IP ADDRESS -all"

Once you have published your SPF records, let Microsoft/Hotmail know by submitting your domain to the following form:

http://support.msn.com/default.aspx?productKey=senderid&mkt=en-us

Verify Everything is Setup Properly

After SPF records have been published, test your SPF records using a general DNS tool, or go here:

http://www.kitterman.com/spf/validate.html

Once SPF records have been published, users typically experience a gradual improvement in delivery over 1 to 2 months.

More Information

Please visit the following links for valuable information and tools on SPF records:

http://www.openspf.org/

http://www.smartbiz.com/article/view/2320/1/53