What is SPF?

This is a common question when email fails

A customer tells you that your messages go to spam. Another says that Gmail or Microsoft shows warnings. Or an external service asks you to configure SPF before it can send email with your domain.

At that point, it is normal to ask what SPF actually is and whether it is essential.

The short answer is that SPF helps other mail servers check whether a server is authorised to send email for your domain.

It is not the only check used by spam filters, but it is an important part of modern email configuration.

Quick answer

SPF means Sender Policy Framework.

It is a rule published in the domain's DNS that says which servers may send email using that domain.

For example, if your domain is domain.com, the SPF record indicates whether PRIMARI.NET servers, or another authorised service, may send email for domain.com.

When a server receives a message, it can query the domain's DNS and ask:

Was this server allowed to send this email?

If the answer is coherent, the message has more credibility. If the answer fails or does not exist, the message may look suspicious.

Why is it important?

Without SPF, it is easier for someone to try to send fake emails pretending to come from your domain.

That does not mean that anyone can log in to your mailbox. These are different things.

SPF does not protect the mailbox password. SPF helps receiving servers distinguish between authorised servers and servers that should not be sending email for that domain.

This is especially important when:

• you send business email from your domain;
• you use external services to send newsletters, invoices or notifications;
• some messages arrive in spam;
• Gmail, Microsoft or other providers show warnings;
• you want to reduce attempts to spoof your domain.

What is an SPF record in DNS?

SPF is normally published as a TXT record in the domain's DNS.

The content of the record usually starts with:

v=spf1

After that, the authorised servers or services are listed.

Do not copy a generic example from the Internet without adapting it. The correct record depends on who really sends email for your domain.

A domain should have only one SPF record

A very common mistake is creating more than one SPF record for the same domain.

For example, one provider asks you to add SPF, then another service asks for it too, and the domain ends up with two separate records that start with v=spf1.

That is usually incorrect.

Normally the domain should have a single SPF record, and the authorised services should be combined inside that one record.

If an SPF record already exists, do not delete or replace it without understanding what it authorises. You could stop email that was working correctly before.

SPF does not solve everything

SPF is important, but it does not guarantee that every email will always reach the inbox.

Large providers may also consider:

• the reputation of the sending server;
• whether the message looks like spam;
• whether the domain has DKIM;
• whether the domain has DMARC;
• previous recipient behaviour;
• whether users have marked messages as spam.

So configuring SPF is part of the solution, not an absolute guarantee.

Common mistakes

The most common mistakes are:

• not publishing any SPF record;
• having two or more SPF records on the same domain;
• authorising an old service that is no longer used;
• not authorising a new service that does send email;
• copying a record without understanding it;
• changing DNS for the wrong domain;
• expecting the change to be visible immediately everywhere on the Internet.

It is also common to confuse SPF with other email mechanisms. SPF, DKIM and DMARC are related, but they do not do the same thing.

What can you check yourself?

Before making changes, review these questions:

• Who really sends email for the domain?
• Do you only send through PRIMARI.NET, or also through an external service?
• Is there already a TXT record that starts with v=spf1?
• Does the problem affect all recipients or only some?
• Did the problem start after adding a new sending service?

These answers help decide whether an SPF record must be created, corrected or combined.

When to contact PRIMARI.NET

Contact PRIMARI.NET if your emails go to spam, if you do not know which servers should be authorised, or if an SPF record already exists and another service asks you to add another one.

We can review the domain's DNS configuration, identify which services send email, and prepare a coherent SPF record without breaking what already works.