4 Common Mistakes To Avoid While Creating An SPF Record

4 Common Mistakes To Avoid While Creating An SPF Record

Sep 27, 2021, 9:51:59 AM Tech and Science

Sender Policy Framework ( SPF) is an email authentication system that lets you decide the IP addresses to send email from your domain. The servers receiving emails examine the SPF record of all emails that come in. A message sent through your domain can only be authenticated if the IP address is recorded within the SPF record.

Simple and easy to implement, SPF can significantly improve email security and reduce phishing and spam attacks. But, SPF also has some limitations that could make it a bit difficult to use correctly. Here are the 4 most frequent mistakes people make when they implement SPF, which you must be sure to avoid at all costs.


To determine whether an email has passed SPF authentication, the email servers receiving the message might need to perform several DNS lookups. However, to safeguard the receiving mail servers from attacks that could cause a denial of service, they are not allowed to conduct at least 10 lookups when reviewing the SPF record of the inbound email.

If you exceed the DNS limit on lookups, authentication or validation of your domain could be broken, allowing threat actors to use your domain. That means that after the limit is reached, each email that needs the use of a DNS search won't yield the desired outcome. You may receive several messages that do not send out without giving you any warning.

The excessing limit of the SPF 10 lookup limits is among the gravest errors you can commit when making an SPF record. It can affect the reputation of your domain and its ability to deliver. SPF flattening is the most efficient solution to the issues caused by SPF's SPF search limit. Flattening is replacing all domains listed in the SPF record with their IP addresses, and it will eliminate the need for DNS lookups.

EmailAuth is a professionally designed software for protecting your domain's email. It comes with the Automatic Flattening feature that automatically reduces the size of your SPF record, making it easy required on your part.


If you're thinking about what number of SPF records you could have on one domain, the best answer is "ONE". If your domain contains multiple SPF records, nobody can tell which will be used by sending a mail server to search whether they can verify SPF authentication. It can prevent certain genuine emails from getting delivered to your customers, thereby impacting your domain's ability to deliver emails at a high rate.

Check that the DNS query of the type TXT will result in only one TXT record, which begins with the v=spf1. If you are required to add additional features to the SPF record, ensure that you include them in the existing record rather than making a new record.


To ensure the accuracy of your SPF record is functioning correctly, it is crucial to ensure that it's constructed properly. Various frequent syntax errors could result in your emails failing SPF authentication, stopping their delivery.

Here's an example of proper syntax for SPF:

v=spf1 a MX ip4: include:returnpath.com include:xyz.com ~all

Here's an overview of the most frequent syntax mistakes to keep in your head:

  • There shouldn't be any extra spaces before the start of the string (v=spf1)
  • There shouldn't be any extra spaces following the string's conclusion (~all)
  • Verify that there aren't any spelling errors in any records' mechanisms, such as include, ip4, etc.
  • Be sure that there aren't any spelling mistakes within any domains that are referenced.
  • Take out any uppercase characters that are in the Ip6 or IP4 mechanisms.
  • Eliminate any special characters such as dashes before using the fail-hard mechanism. For example, substitute -all for -all.
  • Check that there is one space and there are no commas between each mechanism.
  • Be sure to start your string with v=spf1 rather than any other mechanism, such as IP4.


Many people safeguard their active mail sending domains by using SPF and do not bother to put all that effort into making an SPF record of domains that aren't sending mail. Cybercriminals frequently spoof domains that don't send mail to bypass the defences of an organization. If you own several domains which don't send emails, the most effective thing you can do is create null SPF records for them.

The publication of a null SPF record ("v=spf1 -all") for any domain explicitly states that the domain doesn't send emails. For instance, if your domain example.com isn't used to send emails, you could create the following SPF record for it:

"v=spf1 a:mail.example.com -all"

Keep these common SPF mistakes in mind when you create an SPF account for the domain you are using to ensure that you are providing the proper security for your email.


Published by nimisha rawat


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