SPF (Sender Policy Framework) Validation tool allows users to determine whether there exists some SPF record in type TXT of DNS records of the subjected domain or host. The validation is done by validating the format of SPF records of the domain and determining if the data is valid and should be working or not.
SPF stands for Sender Policy Framework. It's a TXT record added to a domain DNS record that specifies the IP addresses allowed to send emails on behalf of the domain. It enables the domain to announce the list of approved senders publicly.
The SPF record does not validate against the From domain. Instead, it looks at the Return-Path to validate the originating server. Return-Path is the mailing address that receiving mail servers use to notify the problems like delivery problems to the sending mail servers. Therefore, your email can pass the SPF record validation even if From address is fake. The only limitation is that the recipient sees the From address in its email client.
So if the message fails SPF validation, there is no guarantee that it would not be delivered. The receiving ISP takes the final decision. Therefore, SPF is one of the many factors that determine either email should be delivered or not. However, when it comes to verifying the From address, DMARC is relatively more reliable than SPF.
The battle against spam and email scam continues. With time, several standards have developed to stop that practices. Sender Policy Framework or SPF is one of those standards.
SPF record determines which email servers are authorized to send the email(s) on the domain's behalf. Results in preventing spoofing and phishing attacks against the email domain. The SPF record describes the DNS record in a particular format to list all the hosts allowed to send the emails on the domain's behalf.
An email can be delivered without SPF authentication. It's not a perfect solution and ultimate problem resolver. However, if combined with DKIM and DMARC, it can improve your email delivery rate and prevent abuse.
The process is quite simple. Suppose an email server receives the message and checks its Return-Path. Suppose that path is [email protected]. To perform the SPF lookup or to validate the SPF record, the following steps take place.
Implementing an SPF record is an easy process. It's a TXT record that you need to add to your DNS record. One common mistake that people usually make is setting the multiple SPF TXT entries in their DNS records, making the receiving server challenging to know which SPF record is the definitive one. That results in failing SPF record validation.
So, whenever you want to add the SPF TXT record for the new server. Always make sure to delete the existing SPF record entry. Just add the new service to that entry.Example of an SPF record
An SPF syntax looks like this:
v=spf1 include:_spf.google.com ~all
v=spf1 is the version of the SPF record being used followed by one or mechanisms. The mechanisms that follow are checked left to right, and these specify different rules on how SPF is checked for the domain.
v=spf1 include:send.aweber.com ~all
v=spf1 include:amazonses.com ~all
v=spf1 include:spf.messagingengine.com ?all
v=spf1 include:_spf.google.com ~all
v=spf1 a mx include:secureserver.net ~all
v=spf1 include:u123456.wl.sendgrid.net -all
v=spf1 include:spf.mandrillapp.com ?all
v=spf1 include:spf.protection.outlook.com -all
v=spf1 include:mailgun.org ~all
v=spf1 include:spf.mailjet.com ~all
v=spf1 include:_spf.mlsend.com ~all
v=spf1 include:emailsrvr.com ~all
v=spf1 include:zoho.com -all
v=spf1 include:mail.zendesk.com ?all
To validate the SPF record. Perform the following steps.