SPF macros are getting more attention lately because they make SPF records easier to handle. Instead of stuffing your SPF record with every single sending source, an SPF macro can pull small bits of information from each email during validation. This keeps your record lighter and far easier to update while also helping mailbox providers run cleaner checks.
In this blog, we will discuss how these macros work, where they help, and how you can use them safely.
What are SPF Macros
SPF macros are special character sequences that make an SPF record more flexible. They replace certain parts of the SPF DNS TXT record during the authentication process. Most SPF records use basic mechanisms and qualifiers, which work fine for simple setups. But when a domain has many sending services or needs more dynamic checks, SPF macros come in handy.
A typical SPF macro starts with a percent sign and uses letters, modifiers, and delimiters to pull specific details from the incoming email. It’s recommended to use them so that you gain better control over your SPF record. Although they are not yet widely used, they can make SPF policies more adaptable and simplify management for complex setups.
Types of SPF Macros
SPF macros are shown as single letters or symbols inside curly braces, and they always start with a percent sign. Here are some of the most used ones-
- %{s}: This picks up the full sender email address. For example, [email protected].
- %{l}: This shows only the local part of the address. In this case, just ‘finance.’
- %{o}: This points to the sender’s domain, like example.com.
- %{d}: This shows the domain that is actually responsible for sending the email. Most of the time, it matches the sender’s domain, but sometimes it differs.
- %{i}: This pulls the IP address of the sender, for example, 192.157.1.110.
- %{h}: This shows the hostname used during the HELO or EHLO greeting in SMTP.
How Do SPF Macros Work
SPF macros basically help your SPF record adjust itself based on the email that is being checked. Instead of writing every tiny detail inside the record, you put a small code called an SPF macro. When an email is sent, the receiving server reads these macros and replaces them with actual information, such as the sender’s IP address or domain. This makes the SPF record much easier to manage.
Here is a simple example:
v=spf1 include:%{i}_.%{d}._spf.example.com ~all
In this include part, %{i} stands for the sender’s IP address and %{d} stands for the domain in the MAIL FROM command. When the email reaches the receiving server, it checks the SPF record, finds these macros, and replaces them with the actual values. So if the IP is 192.157.1.110 and the domain is example.com, the SPF record expands using that information.
After expanding the record, the server checks if the IP and the domain are allowed to send mail for that domain. If yes, the email passes SPF. This is why SPF macros are so useful. They make things simpler and work well when your email setup keeps changing. If you ever want to see how your SPF record behaves, you can test it easily with the SPF Lookup.
Common Cases for Using SPF Macros
Not all SPF records require SPF macros. Here are the usual conditions in which you may include them:
The Setup Involves Multiple Domains
SPF macros are handy when a company owns many domains and needs to manage email authentication across them. Instead of creating separate SPF records for every domain, macros let you build one flexible setup that adjusts itself based on the email being checked. This saves time and keeps the whole system cleaner.
It’s also better than SPF flattening, since it keeps the record lighter and requires fewer updates. This setup stays easier to manage even when routing or sending rules change.
Large and Complex Infrastructures
Some organizations use multiple tools to send email, such as marketing platforms, support desks, or automated systems. This can quickly make an SPF record long and confusing. SPF macros solve this by letting you reference important details without listing every mechanism directly.
This way, the record is shortened and remains within the 512-octet limit. So, when the receiving server looks at the SPF record, it simply fills in the macro values by itself. This ultimately makes the whole checking process run smoothly, even if the setup is big or messy.
Inclusion of Multiple Third-Party Service Providers
If your company uses many external email services, SPF macros can make things much easier. Normally, adding too many third-party ‘include’ statements can push up DNS lookups and sometimes even cause void lookup errors.
SPF Macros help you keep these includes simple so your SPF record stays within safe limits. They also lower the chance of the TXT record breaking if a vendor changes its sending IPs.
SPF Macros Vs SPF Flattening
SPF macros and SPF flattening both try to make SPF records easier to handle, but they work very differently. SPF flattening creates a single, consolidated list of all the IPs used by your email services. It looks simple at first, but it can make the record very long. If any vendor changes an IP range, the whole record becomes outdated, and you need to rebuild it. This also increases the chance of hitting DNS limits or breaking the record without noticing.
SPF macros take a cleaner and smarter approach. Instead of hard-coding every IP, the record pulls the right information during the SPF check. This keeps the record short and much easier to maintain. It also adjusts better when your email setup changes because the server fills in the details on the spot.
Overall, SPF macros are the better choice because they lower manual updates, avoid DNS lookup issues, support changing systems, and keep your record more stable.
Simplifying SPF Records With SPF Macros
SPF macros make it easier to handle complex email setups without turning your SPF record into a long and messy list. They let the record pull the right information during the check, so you do not have to update it again and again. This helps keep your email authentication clean, safe, and simple. Even if your company uses many tools or vendors, SPF macros can keep the record steady and easy to manage.
But we know that adding SPF macros can still feel confusing. If you are not sure how to set them up, you can always reach out. The EasyDMARC team can help you create the correct SPF record and make sure everything works smoothly.
Frequently Asked Questions
SPF macros are small codes inside an SPF record that get replaced with real information during email checks. They can pull details like the sender’s IP address or domain. This helps the SPF record stay simple and flexible. Instead of writing everything manually, the server fills in these values on its own. This makes SPF easier to manage, especially if you use many tools or send emails from different places.
Domain owners use SPF macros to keep their SPF records clean and easy to update. If they depend on many sending tools, the record can quickly get long and confusing. Macros help avoid that by pulling the right information at the time of validation. This reduces mistakes, keeps the record lighter, and helps pass SPF checks more reliably. It also saves time because there is no need to rewrite the record after every change.
Large setups often include marketing tools, support systems, and automated senders. Adding all their IPs can make the SPF record too long. SPF macros fix this by letting the server fetch the details when needed. This keeps the record short and within DNS limits. It also reduces the chance of breaking the record when a vendor updates its IP ranges. For companies with many systems, macros make SPF safer and easier to handle.
Yes, in most cases, SPF macros work better. SPF flattening lists every IP, which can make the record too long and hard to maintain. If a vendor changes its IPs, the flattened record becomes outdated. SPF macros avoid this problem because they pull the information in real time. The record stays short and auto-adjusts during checks. This makes it more stable, more accurate, and easier to manage for changing setups.
SPF macros can feel a bit confusing at first because they look like small codes. But once you understand what each SPF macro stands for, using them becomes much easier. They help simplify complex SPF records and reduce manual updates. If you are still unsure, you can ask experts or use tools that check your SPF record for mistakes. Many domain owners rely on EasyDMARC to correctly set up macro-based SPF records.
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