How to Set Up SPF

Prerequisites

Before setting up SPF, make sure you have:

• A domain name you control
• Access to DNS management
• Your email server IP address

Step 1: Determine Your SPF Record

The SPF record is a DNS TXT record that lists authorized email servers for your domain.

Basic format:

v=spf1 ip4:YOUR_VPS_IP a mx ~all

Common SPF Mechanisms

• ip4:IP – Allow a specific IPv4 address
• ip6:IPv6 – Allow specific IPv6
• a – Allow the domain's A record IP
• mx – Allow the domain's MX record IPs
• include:example.com – Include another domain's SPF record

Qualifiers (Ending of SPF record)

• + – Pass (default)
• - – Fail (hard fail – recommended)
• ~ – SoftFail (accept but mark as suspicious)
• ? – Neutral

Step 2: Build Your SPF Record

Example for VPS sending email directly:

v=spf1 ip4:148.113.173.106 -all

Example using include for email service (e.g., SendGrid):

v=spf1 ip4:148.113.173.106 include:sendgrid.net -all

Step 3: Add SPF Record to DNS

In your domain's DNS settings, create a TXT record:

• Name/Host: @ (or your domain)
• TTL: 3600
• Value: v=spf1 ip4:148.113.173.106 -all

If your provider requires separate host, use the domain itself.

Step 4: Verify SPF Record

Use dig:

dig txt example.com +short

Or online tools like MXToolbox SPF Check.

Step 5: Test Email for SPF

Send an email to a Gmail account and check the original headers for:

Authentication-Results: spf=pass