The digital landscape is full of malicious actors who are always on the lookout for unprotected and vulnerable email-sending domains that they can exploit to send fraudulent phishing email messages, masquerading as someone from reputed companies. The combination of SPF, DKIM, and DMARC shields business domains from their evil eyes by allowing only trusted people to send emails on their behalf.
SPF (Sender Policy Framework) is the basic email authentication protocol where domain owners specify all the IP addresses (belonging to the ipv4 and ipv6 address range) and mail servers that they trust and allow sending emails from. Any message dispatched from the sending source outside of this list either gets placed as spam or bounces back.
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All this involves an SPF record which is a TXT record updated on your domain’s DNS so that recipients’ mail servers can retrieve and refer it to verify if a particular sender is authorized. If the sender is legitimate, the email lands in the primary inbox; otherwise, it may get flagged as spam or even rejected.
Problems of Having Multiple SPF Records
While domain owners or administrators create multiple SPF TXT records to improve email deliverability and security, it leads to complications. In some cases, the presence of multiple SPF records leads to the invalidation of all the records.
You can know about this issue if you run your record through an SPF check tool. You can also know about a number of other issues- for example, the use of mx and ptr mechanisms, incorrect use of the ‘all’ tag, inclusion of an invalid IP address and mail server, etc.
Now, here are some of the issues that arise due to the existence of multiple SPF TXT records on a single domain’s DNS.
There will be conflicts in the information stated in different records, which will make it challenging for the receiving server to confirm if a sender is permitted to transmit emails on behalf of the organization or not. This confusion can also have your genuine emails being marked as spam, creating problems for the marketing and customer support teams.
Delays in Email Delivery
Having more than one SPF record increases the DNS lookup time during the SPF email verification process and can lead to considerable delays in deliveries.
Complex Management and Debugging
It can be difficult for the person handling all the SPF TXT records for your domain to stay consistent with configurations, which eventually causes errors.
Moreover, it becomes a headache to identify and troubleshoot a problem or error as you will have to dig through every part of all the DNS records.
Increased Risk of Phishing and Spoofing
An error makes a record invalid, which gives cybercriminals opportunities to exploit a domain or subdomain and send fraudulent emails by impersonating reputed and trusted entities.
Lack of Clarity
Multiple SPF records can create confusion for both senders and recipients. Senders might not be sure which record to follow, while recipients may be uncertain about the authenticity of the emails they receive.
How to Merge Multiple SPF Records?
The answer to ‘how to fix the issue of multiple SPF DNS records’ is nothing but the consolidation of these records into a single one. Now note, that you can’t do this by simply copying and pasting multiple strings into one. This has to be done following a rule, otherwise, you will encounter failed DNS lookups.
Here’s a step-by-step guide on the right way to merge multiple SPF DNS records-
Choose the Base Record
Select an existing SPF DNS record to which you would make all the changes. It’s best to pick the one that’s most comprehensive and up-to-date.
Copy the contents of the chosen base SPF record into a text editor or SPF record generator tool. Add the entries from the other SPF records to the base record, ensuring there are no duplicates or conflicting directives.
Use the Include Mechanism
Now use ‘include’ statements to add IPs of a third-party vendor who you need to send emails on your behalf. This way, you don’t have to list every IP address individually, which uncomplicated the DNS record and eliminates the need for DNS lookups.
Set the Limit
There’s a limit of a maximum of 10 DNS lookups, so, ensure the number of include mechanisms are limited as every instance is counted towards it. Exceeding this limit causes an SPF permerror.
Test and Validate
Before publishing the merged record on DNS, perform an SPF check using a dedicated tool to ensure there are no errors. Simulate an SPF authentication check to verify the record is working properly.
Update DNS Settings
The next step is to go to your domain’s DNS management console and replace the existing SPF records with the newly consolidated one.
Monitor and Maintain
You must periodically and frequently run it through an SPF record checker for a non-erroneous record and effective SPF authentication process.
There should be no more than one SPF TXT record per domain name. If there are multiple SPF TXT type records, then you need to consolidate them using include mechanisms and getting rid of redundant syntax.