Email security is a critical issue for both personal and business communication. Reputable email hosting services take great care to secure your emails against cyber threats. To secure your emails, it is essential to use authentication protocols like DMARC, SPF, and DKIM.
These protocols help ensure that the email messages are from you, not someone trying to impersonate you. Using authentication protocols, you can protect yourself from spam and malware and safeguard your privacy.
Let’s take a closer look at each of them.
What is an SPF Record?
An SPF record is a DNS record that indicates which mail servers are authorised to send an email on behalf of your domain. By publishing an SPF record, you can help prevent email spoofing and protect your recipients from phishing attacks.
Email spoofing is when someone sends an email that appears from you but is actually from another source. This can be done for malicious reasons, such as trying to trick someone into giving up their password or clicking on a malicious link.
Email spoofing often uses phishing attacks to trick the recipient into divulging personal information or clicking on a malicious link.
By publishing an SPF record, you can specify which mail servers are allowed to send emails on behalf of your domain. This helps prevent email spoofing, as any email sent from a server not included in your SPF record will fail authentication.
You can use MXToolBox’s SPF Tool to check your SPF record.
What is a DKIM Record?
A DKIM record is a DNS record used to sign email messages digitally. By signing your email with DKIM, you can help ensure that the message has not been tampered with and is actually from you.
DKIM uses public-key encryption to sign email messages. When a notification is signed with DKIM, a digital signature (not to be confused with an email signature) is added to the message header. This signature can be verified by anyone who receives the message to confirm that the message is from the person who claims to have sent it.
To check your DKIM Record, you can use this tool.
What is a DMARC Record, and What is it Used for?
A DMARC record is a DNS record used to help prevent email spoofing. DMARC stands for “Domain-based Message Authentication, Reporting, and Conformance.”
DMARC works by combining SPF and DKIM authentication. It uses both methods to verify an email message from the person who claims to have sent it.
To use DMARC, you must first have both SPF and DKIM set up and working on your domain. Once you have done this, you can then create a DMARC record.
A DMARC record contains two essential parts: a policy and a report address. The policy specifies what should happen if an email fails authentication. The report address is where you will receive reports about any email that fails authentication.
By publishing a DMARC record, you can help to prevent email spoofing and protect your recipients from phishing attacks.
How to set up DMARC for your email domain
DMARC is set up using a DNS TXT record. The following is an example of the syntax for a DMARC record:
_dmarc.example.com IN TXT “v=DMARC1; p=reject; rua=mailto:[email protected]”
The above example has the following parts:
- The DMARC record’s name is “_dmarc.example.com” in this case.
- The type of DMARC record, which is TXT.
- The value of the DMARC record contains the policy and report address. In this case, the policy is to “reject” any email that fails authentication, and the report address is “[email protected]”
Set up a DMARC policy. The DMARC policy specifies what should happen if an email fails authentication. There are three possible policies:
- “none“: No action is taken if an email fails authentication. This is the default policy.
- “quarantine“: Emails that fail authentication are sent to a spam folder or similar.
- “reject“: Emails that fail authentication are not delivered, and you will receive a bounce message.
Set up a report address. The report address is where you will receive reports about any email that fails authentication. This can be an email address or a URL.
Publish your DMARC record. Once you have set up your DMARC record, you need to publish it in DNS. Using a DNS management tool such as BIND or PowerDNS can be done.
Test your DMARC record. You can use a tool such as MXToolBox’s DMARC Check Tool to test your DMARC record and ensure it works correctly.
Finally, once your DMARC is set up, you can start monitoring the reports you receive from the report address. These reports will tell you if any email is failing authentication. You can then take action on any email that fails authentication according to the policy specified in your DMARC record.
Tips for using DMARC to protect your email from spam and phishing attacks
- Use a strong DKIM key: A stronger DKIM key will make it more difficult for attackers to spoof your email.
- Use DMARC with SPF and DKIM: Using all three methods, you can provide the strongest possible protection against email spoofing.
- Monitor your DMARC reports: By monitoring your DMARC reports, you can take action on any email that fails authentication. This will help to protect your recipients from phishing attacks.
- Use a “reject” policy: The “reject” policy is the most effective at preventing email spoofing. However, it may also result in some legitimate emails being rejected. If you use this policy, you should monitor your DMARC reports carefully to ensure that
How to troubleshoot problems with DMARC
If you are having problems with DMARC, there are a few things that you can do to troubleshoot the issue.
First, check your DNS settings to ensure your DMARC record is published correctly. If you use a DNS management tool such as BIND or PowerDNS, you can use the ” dig” command to query your DNS server and check the DMARC record.
Second, check the email headers to see if there is a DMARC authentication failure. A “DMARC-Failure” header will usually indicate this.
Third, check your DMARC reports to see if any emails fail authentication. You can use a tool such as the DMARC Report Analyzer to analyse your DMARC reports.
Fourth, if you use the “reject” policy, check if any legitimate emails are being rejected. You can do this by monitoring your bounces and looking for any email addresses consistently bouncing.
Finally, you can contact your web host for help if you still have problems.
Examples of how DMARC has been used to stop email-based attacks
In 2014, DMARC was used to prevent a phishing attack targeting Gmail – the popular email service. The episode spoofed the “from” address of the email so that it appeared to come from Gmail and included a link to a fake login page. DMARC detects spoofed emails and blocks them before reaching users’ inboxes.
In 2014, DMARC was used to stop a phishing attack targeting users of the famous company Apple. The attack used spoofed emails and malicious attachments to try and trick users into revealing their login credentials. DMARC detects spoofed emails and blocks them before reaching users’ inboxes.
A report by Valimail claims that “Only 14% of domains worldwide truly protected from spoofing with DMARC enforcement. While the DMARC enforcement rate increases, 3 billion messages per day are still spoofing the sender’s identity”. That is shocking – to say the least – since it has been over ten years since the DMARC standard was first published.
DMARC is an effective tool for stopping email-based attacks. Using DMARC, you can protect your recipients from phishing attacks and other email-based threats.