Multiple SPF Record Error and Solutions

Email security has become more important than ever. Various methods are used to prevent sent emails from ending up in recipients' spam folders and to protect against email phishing attacks. One of these is the Sender Policy Framework (SPF) record. An SPF record specifies which servers are authorized to send emails on behalf of a domain. However, having multiple SPF records can lead to problems with email delivery, which can negatively impact the success of your email marketing campaigns. In this article, we will examine in detail what multiple SPF records mean, why they cause problems, and the methods you can use to solve this problem.

What is an SPF Record and Why is it Important?

SPF (Sender Policy Framework) is a TXT record that defines which servers are authorized to send emails from a domain. Email receiving servers check the SPF record of an email to verify whether the email was actually sent from the specified domain. If the email does not come from a server specified in the SPF record, the receiving server may mark the email as spam or reject it completely. Therefore, the SPF record is critical to protect your email reputation and ensure that your emails reach recipients' inboxes.

Proper configuration of the SPF record increases reliability in email marketing, customer relationship management (CRM), and other email communications. A misconfigured or incomplete SPF record can cause your emails to be marked as spam or even completely rejected, which can seriously affect your business communication.

Why Do Multiple SPF Records Cause Problems?

According to the RFC 7208 standard, there should be only one SPF record for a domain. Multiple SPF records complicate the process of email receiving servers evaluating the SPF record and often result in a permanent error called "PermError". This error causes the receiving server to be unable to determine which SPF record is valid, and the email's authentication fails. As a result, the likelihood of your emails being marked as spam or rejected increases significantly.

Common reasons for multiple SPF records include:

Using different email service providers (ESPs) and adding their own SPF record.
Forgetting to delete old or unused SPF records.
Misunderstanding the syntax of the SPF record and unnecessarily creating multiple records.

How to Detect Multiple SPF Record Issues?

You can use various online tools and command-line tools to check if you have multiple SPF records. Here are some methods:

1. Online SPF Check Tools

Various websites allow you to check SPF records for your domain. When you enter your domain into these tools, they scan the DNS records and display the number and content of SPF records. For example, tools like "MXToolbox" or "SPF Check" can be used for this purpose.

2. Command Line Tools (nslookup, dig)

You can also check your SPF records by querying DNS records via the command line. For example, on Linux or macOS, you can query using the "dig" command as follows:

dig TXT yourdomain.com

On Windows, you can use the "nslookup" command:

nslookup -type=TXT yourdomain.com

These commands display the TXT records (including SPF records) for your domain. If you see more than one record starting with "v=spf1", you have multiple SPF records.

How to Fix Multiple SPF Record Issues?

After detecting the multiple SPF record issue, you can follow these steps to resolve it:

1. Merge All SPF Records

The best solution is to merge all SPF records into a single record. This means specifying all your authorized sending sources in a single SPF record. For example, if you send emails from both your own server and an email marketing service, you should specify both sources in a single SPF record.

An example of a merged SPF record:

v=spf1 ip4:192.0.2.0/24 include:spf.example.com include:_spf.google.com -all

In this example:

ip4:192.0.2.0/24: This specifies the IP address range of your own server.
include:spf.example.com: This includes the SPF record of another domain (for example, the SPF record of your email marketing service).
include:_spf.google.com: This includes Google's SPF record if you are using Google Workspace (formerly G Suite).
-all: This specifies that emails from all other sources not specified in the SPF record should be rejected.

Important: Make sure the merged SPF record does not exceed the 255 character limit. Also, avoid using more than 10 "include" statements, as this can also cause SPF evaluation errors.

2. Delete Extra SPF Records

After merging all SPF records into a single record, delete all other SPF records from your DNS settings. This ensures that receiving servers only encounter one SPF record and that the authentication process is completed correctly.

3. Make Sure the SPF Record Has the Correct Syntax

Make sure the SPF record has the correct syntax. Incorrect syntax can prevent the SPF record from being evaluated correctly. The basic components of an SPF record are:

v=spf1: Specifies the version of the SPF record.
ip4: and ip6:: Specifies specific IP addresses or IP address ranges.
include:: Includes the SPF record of another domain.
a: Specifies the IP addresses specified in the A record of the domain.
mx: Specifies the IP addresses of the servers specified in the MX record of the domain.
ptr: (Not recommended) Checks if the IP address matches the domain by performing a reverse DNS lookup.
exists:: Checks if a specific domain exists.
redirect=: Redirects the SPF record to another domain.
all: Specifies all other sources. Can be used as +all (allow), -all (reject), ~all (soft fail), or ?all (neutral).

4. Check Your SPF Record Regularly

It is important to check and update your SPF record regularly as you make changes to your email infrastructure or the services you use. For example, when you start using a new email marketing service or your server's IP address changes, you should update your SPF record accordingly.

Example Scenario: Fixing Multiple SPF Records

Let's say you have the following two SPF records for your "example.com" domain:

v=spf1 ip4:192.168.1.10 -all

v=spf1 include:spf.mailjet.com -all

In this case, you need to merge these two records into a single record. For example:

v=spf1 ip4:192.168.1.10 include:spf.mailjet.com -all

This new SPF record specifies that both your own server (192.168.1.10) and Mailjet (spf.mailjet.com) are authorized to send emails. Then, you need to delete the old SPF records from your DNS settings.

Conclusion and Summary

Having multiple SPF records can lead to serious problems with email delivery. In this article, we examined in detail what multiple SPF records mean, why they cause problems, and the methods you can use to solve this problem. In summary, there should be only one SPF record for a domain, and this record should specify all your authorized sending sources. Regularly checking and updating your SPF record is critical to protect your email reputation and ensure that your emails reach recipients' inboxes.