An SPF record can be a powerful tool for email authentication to keep spamming and phishing attempts in check.
Email is an essential means of business communication as it is quick, cheap, and easily accessible. But the increased reports of phishing and spam messages call for stricter email authentication methods. One such open standard email authentication method is the Sender Policy Framework (SPF).
In this article, we’ll explore everything you wanted to know about email authentication and SPF records, including its working, creation, and validation.
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Email authentication enables businesses to provide authenticity to emails sent to their customers. With email authentication in place, you don’t need to worry about phishing messages representing your domain. It also increases the deliverability of your emails.
Sender Policy Framework (SPF) record is an open standard used by businesses worldwide for email authentication. SPF ensures safer delivery of emails and prevents malicious actors from using your domain to send nefarious/spam emails.
With SPF in place, no one other than the authorized email server can send emails to your customers from your domain. Any attempt from malicious actors to violate it will get blocked by the recipient’s email servers.
An SPF record is a TXT record that provides a list of IP addresses/hostnames which can send emails on behalf of a particular domain. Only one SPF record is allowed per domain, and multiple records will lead to SPF record check failure.
Spammers and malicious actors often forge your email header to send spam emails. It could look like you are sending those emails as they use your email address. But with SPF in place, such spoofing attempts are prevented to a large extent.
After creating an SPF record, it is added to the DNS Database. An SPF record will look similar to the one below:
yourdomain.com TXT "v=spf1 include:yourdomain1.com include:yourdomain2.com ~all”
Let’s decode the SPF record provided above as follows.
It states that any email originating from the domain yourdomain.com needs to undergo an SPF check. Furthermore, it states that the following domains, yourdomain1.com and yourdomain2.com, are authorized to send emails on behalf of your domain. Any other IP addresses or domains that send an email from your domain fail the SPF test and should be flagged.
Let’s take a look at the SPF record check flow in simple steps:
When it comes to creating an SPF record, one should carefully follow every guideline for creating an SPF record. Important points to remember while generating an SPF record are:
Q. Will the email be returned to the sender if it fails the SPF record check?
Ans: It entirely depends on how the recipient email server operates. Some email servers bounce back the email, while some ignore all email messages that fail the SPF check.
Q. What will happen if your SPF record has more than 10 DNS lookups?
Ans: It is more likely that your email will end up in the spam folder or get bounced back.
Q. How can you check how many DNS lookups your SPF record has?
Ans: Many online tools help you check the number of DNS lookups for your SPF record.
Q. How can you check if an SPF record exists for your domain?
Ans: To check whether an SPF record exists for your domain, you can use one of the SPF tools available online. It will tell you whether an SPF record exists and runs several tests on the record to determine the number of DNS lookups. It also notifies if any issues are encountered with your record.
Q. When you add an SPF record, is it possible to understand the number of emails getting blocked due to an SPF record check fail?
Ans: It is impossible to determine the number of email messages getting blocked just by adding an SPF record. You may check for any dedicated services or packages to find out the number.
Q. Can you use SPF with dynamic IP addresses?
Ans: Yes, you can use dynamic addresses. However, email servers could use Spamhaus policy and hence wouldn’t accept dynamic IP addresses most of the time.
The above discussion can form the basis for the knowledge on SPF records for anyone interested in deploying it for email authentication. By applying appropriate methods for creating and implementing SPF records, one can efficiently block any spoofing attempts of one’s domain by malicious actors. It keeps away the threats of phishing and spam using a particular domain’s credentials to a significant extent.
