SPF Records to Enhance Email Security Introduction
SPF record (Sender Policy Framework) is a method to keep your email safe. But how SPF records can protect our emails? where scammers use advanced technology for scamming. How much email security SPF will provide? And What is the right method to implement SPF records for better results?
Everyone wants to protect their sensitive information, no matter it is businesses or individuals. Secure delivery of your email helps to improve the sender’s reputation, email deliverability, customer trust, and overall email campaign.
So, let’s find out
What is an SPF records?
SPF record (Sender Policy Framework) is an authentication method to spot forged sender addresses during email delivery. This helps to protect senders and recipients from spam, spoofing, email scam, and phishing.
This is a TXT file that contains the authorized IP addresses of senders. After collecting all IP addresses, you need to publish them in your Domain Name System (DNS). This will help to block spammers from sending fake emails. In this, the SPF records matches the sender’s IP addresses to make sure the authorization of it.
An SPF record helps to
- Preventing attacks: SPF records help protect prevent email spoofing and unauthorized use of domains for sending emails.
- Improving email deliverability: It verifies the legitimacy of the sender’s IP address and mail servers to make sure delivery of your emails.
- Enhanced Domain Reputation: To keep your domain safe, use SPF records. They authorize specific IP addresses to send emails to protect your users from harm.
- DMARC compliance: DMARC is like a helper for SPF. It helps to improve email deliverability and avoid being flagged as spam.
How do SPF records work?
When you send an email, it goes through different stages. In this process, the SPF record helps to determine the legitimacy of the sending mail server. Here’s a step-by-step explanation of how SPF records work:
Mail Server: When the sender sends an email it goes through the recipient mail server where SPF records authenticate this mail. This establishes an authentication policy to send emails from a particular domain.
DNS Lookup: The recipient’s mail server checks the domain’s DNS to verify this email by looking at the SPF records. Here, the domain name should be listed as the “envelope from” address. The SPF record contains a list of authorized mail servers.
Verification: Now, the recipient’s mail server checks whether the IP address of the mail server that sent the email matches any of the IP addresses listed as valid senders for the domain in the SPF records.
The email is considered legitimate if the IP address matches one of the authorized mail servers.
If it does not match, It is marked as spam.
For Example, A server with the IP address ‘126.96.36.199’ sends an email by using ‘[email protected]‘ email address. When the recipient’s server checks the SPF record, checks out the domain’s DNS records for school.com. if the IP address matches one of the authorized mail servers in the SPF records, it is considered valid. And If it does not match, It is marked as spam.
How to create a common SPF record?
Here are a few steps to follow for creating an SPF record.
Step 1: Preparation
Check if your email service uses your domain (Return-Path) for sending emails. You need to collect all IP addresses and the mail server will be specified as authorized in the SPF record.
Step 2 DNS control panel
Now you need to access the DNS control panel of your ISP and Look for the section that contains the TXT type record. This is where you can add and manage the SPF record for your domain.
Step 3 – SPF record
You can start your SPF record with the version tag: v=spf1. The next versions can be v=spf2, v=spf3, and so on.
Now, Insert all of your IP addresses that are collected to specify as authorized:
Now you can add the include tag for each third-party email service to designate it as a trustworthy sender:
include:sendgrid.net or include:mandrillapp.com
Now you need to add other mechanisms, qualifiers, and modifiers to create an SPF record.
The final step in creating an SPF record is to set a tag that determines how to handle servers not specified in the record:
- “-all” all unspecified servers are not authorized. so emails will be rejected.
- “~all” all unspecified servers are not authorized. but emails will be accepted and marked as potentially suspicious.
- “+all” all server is authorized
This is the most common SPF record created:
“v=spf1 a mx -all”
Components of an SPF Record
SPF records are made up of various different parts that we describe here. But first, lets look the SPF record syntax example
“v=spf1 +a +mx redirect=example.com -all”
This is used to define the version of the SPF that you are using.
For example, “v=spf1”, It means SPF version 1.
Mechanisms are used to tell which servers are allowed to send emails for that domain. An SPF record has multiple mechanisms in the list. Some common mechanisms
a: This mechanism includes all the IP addresses listed in the DNS A record of the domain. For example, “v=spf1 a:example.com -all”. All IP addresses are associated with “example.com” to send emails.
mx: This mechanism includes all the IP addresses listed in the MX record of the domain’s mail servers. For example, “v=spf1 mx mx:example.com -all”
- include: This mechanism allows you to include specified domains as authorized. For example, “v=spf1 include:spf.example.com -all”.
- ptr: This mechanism is used to check the A records towards the PTR record of each host. For example, “v=spf1 ptr:mail.example.com -all”. If possible, you can try to avoid this mechanism.
- all: matches all remote and local IP addresses and is used at the end. For example, “v=spf1 +all”.
- exists: This specifies domains signed out as exceptions according to the SPF definition. It is rarely used and involves more complicated matches, such as DNSBL queries.
- ip4: This is used to define an IPv4 address in the SPF record. For example, “v=spf1 ip4:192.0.2.1 -all”.
- ip6: It defines an IPv6 address in the SPF record.
- For example, “v=spf1 ip6:2001:0db8::1 -all”.
Quantifiers are a mechanism that use to define how they can handle a match. There are four quantifiers:
- +: the email is from an authorized sender and the email must be accepted.
- -: the email failed the test and the email is rejected.
- ~: the email failed the test but the result is not definite. You can accept the email with a non-compliant tag.
- ?: the test result is neutral and you can accept or reject the email.
Default Rule: If there is no quantifier specified that means it is accepted as +all. So, the email is accepted.
Modifiers are the value that uses the =sign and provide more information. The modifiers are defined as
- Redirect: You can use this mechanism to send a query to other domains. It is useful when you want to use the same SPF record for multiple domains..
- Exp: The “exp” modifier is used to provide an explanation when a FAIL result happens on a matched mechanism. This explanation will be recorded in the SPF log.
So, SPF record (Sender Policy Framework) is an important protocol to keep your email safe. They protect businesses and recipients from spam, spoofing, and phishing. It uses to verify the authenticity of the sender’s IP addresses and mail servers. Also, this helps to prevent email attacks and improves domain reputation. You can create common SPF records using simple steps. SPF records are made up of various different parts including version number, mechanisms, Qualifiers, and Modifiers.
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No, a domain can only have one SPF record. But you can add multiple domains into the same SPF record using mechanisms like “include.”
A misconfigured SPF record can result in email delivery issues. In case, If your SPF record contains errors then some emails will be rejected or marked as suspicious by recipient servers. You need to check and validate your SPF record for accuracy.
It is beneficial to setup SPF record for each subdomain. It helps to improve email deliverability and prevent spam emails.