Email is one of the most widely used communication tools in the world, but it also comes with many security risks. Spammers, phishers, and hackers can use email to send unwanted messages, steal personal information, or impersonate legitimate senders. To protect your email reputation and deliverability, you need to implement three email authentication methods: SPF, DKIM, and DMARC.
What are SPF, DKIM, and DMARC?
SPF, DKIM, and DMARC are techniques that help verify the identity of the email sender and prevent spoofing, which is when someone sends an email pretending to be someone else. These techniques use DNS records to store information about the authorized senders and the policies for handling unauthenticated emails.
SPF
SPF stands for Sender Policy Framework. It is a way for a domain to list all the servers that are allowed to send emails from that domain. For example, if you own example.com, you can create an SPF record that specifies the IP addresses of your email servers. When someone receives an email from user@example.com, they can check the SPF record to see if the email came from one of the authorized servers. If not, the email is likely spoofed and can be rejected or marked as spam.
DKIM
DKIM stands for DomainKeys Identified Mail. It is a way for a domain to digitally sign the emails that it sends, using public-key cryptography. A digital signature is a piece of data that proves that the email was not tampered with and that it came from the domain that it claims to be from. For example, if you own example.com, you can create a DKIM record that stores your public key. When you send an email from user@example.com, you can sign it with your private key, which only you know. When someone receives your email, they can check the DKIM record to get your public key and verify your signature. If the signature is valid, the email is authentic and can be delivered. If not, the email is likely spoofed or modified and can be rejected or marked as spam.
DMARC
DMARC stands for Domain-based Message Authentication, Reporting, and Conformance. It is a way for a domain to specify how the receiving servers should handle the emails that fail SPF or DKIM verification. For example, if you own example.com, you can create a DMARC record that tells the receivers to reject, quarantine, or accept the emails that do not pass SPF or DKIM checks. You can also request feedback reports from the receivers, which can help you monitor your email performance and identify any issues or attacks.
Why are SPF, DKIM, and DMARC important?
SPF, DKIM, and DMARC are important for your email security because they help you:
- Protect your domain reputation: If spammers or hackers use your domain to send malicious emails, your domain reputation can be damaged and your legitimate emails can be blocked or filtered by the receivers. By implementing SPF, DKIM, and DMARC, you can prevent unauthorized use of your domain and ensure that your emails are recognized as trustworthy and reliable.
- Improve your email deliverability: If your emails are not authenticated, they can be rejected or marked as spam by the receivers, which can lower your email deliverability and affect your communication with your customers, partners, or subscribers. By implementing SPF, DKIM, and DMARC, you can increase the chances of your emails reaching the intended recipients and avoid being flagged as spam.
- Prevent email spoofing and phishing: Email spoofing and phishing are common cyberattacks that use fake emails to trick the recipients into clicking on malicious links, downloading malware, or revealing sensitive information. By implementing SPF, DKIM, and DMARC, you can prevent these attacks by making it harder for the attackers to impersonate your domain and deceive your recipients.
How to set up SPF, DKIM, and DMARC?
Setting up SPF, DKIM, and DMARC for your domain requires some technical knowledge and access to your DNS settings. Here are the basic steps to follow:
SPF
- Create a TXT record for your domain with the name @ and the value v=spf1 followed by the list of servers that are allowed to send emails from your domain. You can use different tokens to specify the servers, such as ip4, ip6, a, mx, or include. You can also use modifiers to indicate how strict the receivers should be, such as ~all for soft fail, -all for hard fail, or ?all for neutral. For example, a simple SPF record for example.com could look like this: v=spf1 ip4:123.123.123.123 ~all
- Save the record and wait for the DNS propagation to take effect.
DKIM
- Generate a pair of public and private keys for your domain. You can use online tools or software to do this.
- Create a TXT record for your domain with the name selector._domainkey, where selector is a name that you choose to identify your key. The value of the record should be v=DKIM1 followed by the public key that you generated. For example, a simple DKIM record for example.com could look like this: v=DKIM1; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCrLHiExVd55zd/IQ/J/mRwSRMAocV/hMB3jXwaHH36d9NaVynQFYV8NaWi69c1veUtRzGt7yAioXqLj7Z4TeEUoOLgrKsn8YnckGs9i3B3tVFB+Ch/4mPhXWiNfNdynHWBcPcbJ8kjEQ2U8y78dHZj1YeRXXVvWob2OaKynO8/lQIDAQAB
- Configure your email server or service to sign your outgoing emails with your private key and the selector that you chose.
- Save the record and wait for the DNS propagation to take effect.
DMARC
- Create a TXT record for your domain with the name _dmarc and the value v=DMARC1 followed by the policy and options that you want to apply. You can use different tags to specify the policy and options, such as p for the action to take on unauthenticated emails, rua for the email address to receive aggregate reports, ruf for the email address to receive forensic reports, or pct for the percentage of emails to apply the policy to. For example, a simple DMARC record for example.com could look like this: v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com; ruf=mailto:dmarc@example.com; pct=100
- Save the record and wait for the DNS propagation to take effect.
Summary
SPF, DKIM, and DMARC are essential for your email security and deliverability. They help you authenticate your emails, protect your domain reputation, and prevent spoofing and phishing attacks. To set them up, you need to create DNS records for your domain and configure your email server or service accordingly. By doing so, you can improve your email performance and communication with your recipients.
Next Steps:
risual Ltd provide consultancy services to help your organisation to envision, plan, deploy and assess your email solutions. Should your organisation require help with SPF, DKIM or DMARC or any other part to email messaging, please don’t hesitate to get in touch!
