A guide to the Sender Allow List and Allow List Filtering Rules
This guide explains how to make sure email from people and companies you trust always reaches your inbox, even if the spam filter might otherwise hold it back. SpamExperts gives you two tools for this:
Most of the time the Sender Allow List is all you need. Reach for filtering rules only when a plain sender entry can’t do the job.
Allowing a sender tells the filter: don’t run your spam-content checks on this mail — let it through.
There is one important limit to understand up front:
Allowing a sender only switches off the spam-content scoring. It does not override connection-level rejections.
If the sending mail server is itself on a public blocklist, is badly configured, or fails basic security checks, the message can still be refused before the content filter ever looks at it — and allowing the sender will not force it through. (Blocking, by contrast, always wins.) If you allow a sender and mail still doesn’t arrive, see the Troubleshooting section at the end.
A second thing worth knowing: allowing a sender removes a layer of protection for that address. Spoofed and forged mail that pretends to come from an allowed sender will sail straight through. So allow only what you actually need, and prefer allowing a specific address over a whole domain wherever you can.
Use this when you simply want mail from a particular person or company to always come through.
jane@example.comexample.com (do not put an @ in front of it)The entry appears in the list immediately and takes effect right away.
| You want to… | Enter | Example |
|---|---|---|
| Always receive mail from one person | Their full address | jane@example.com |
| Always receive mail from everyone at a company | Just the domain | example.com |
Recommendation: allow the specific address whenever you can. Allowing an entire domain is convenient but much broader — it also means anyone forging that domain gets a free pass.
Open the same Sender allow list page, find the entry, and click the delete/remove control (usually a trash icon or a Delete link) next to it.
Filtering rules are the more powerful option. Instead of matching only on who sent the mail, a rule can match on the subject line, the To/From/CC headers, the message body, an attachment, the sending server’s IP or hostname, the country of origin, and more. Any incoming message that matches a rule is always allowed.
Use a rule when a plain sender entry isn’t enough — for example:
[INVOICE] in the subject.”You can combine more than one condition in a single rule to make it more precise (for example, match on both the sender and the recipient), which greatly reduces the chance of allowing something you didn’t intend.
These are the most useful match fields for everyday allowlisting, in plain terms:
| Match on | What it means |
|---|---|
| Subject | The subject line of the message. |
| From | The “From” address shown in the message header — what you see in your mail client. Note this is not the same as the true envelope sender, and can be forged. |
| To / CC | The To or CC address in the message header. |
| Sender | The real SMTP envelope sender (the “MAIL FROM” the server actually used). More trustworthy than the header From. |
| Recipient | The real SMTP envelope recipient (who the mail was actually delivered to). |
| Sender IP | The public IP address of the server that sent the mail. |
| Sender Hostname | The reverse-DNS (PTR) name of that sending server. |
| Message Body | Text found in the decoded body of the message. |
| Attachment Name | The filename or extension of an attachment, e.g. .pdf. |
| Attachment Type | The attachment’s MIME type, e.g. application/pdf. |
| Country / Continent | Where the sending server is located. |
Depending on the field, you can refine the match with: Is, Is not, Contains, Does not contain, Starts with, Ends with. (Country and Continent only offer Is / Is not.)
The header From address (what you see) and the envelope Sender address (what the server actually used) are two different things, and legitimate mail doesn’t always make them match. If a rule based on From isn’t catching the mail you expect, look at the message’s raw headers for the exact address in use, or build the rule around the envelope Sender instead — or use both conditions together for the best chance of a reliable match.
Allow everything from one supplier’s real sending address
billing@exmaple.comAllow anything tagged in the subject line
[INVOICE]Allow a specific sender only when it’s addressed to your billing inbox (two conditions in one rule)
example.combilling@yourexample.com| If you want to… | Use |
|---|---|
| Always allow one address or one whole domain | Sender Allow List |
| Allow based on subject, attachment, recipient, IP, country, or several conditions at once | Allow List Filtering Rule |
| Allow a sender whose address keeps changing but who’s identifiable another way | Allow List Filtering Rule |
Start with the Sender Allow List. Only move to a filtering rule when a plain sender entry can’t express what you need.
“I allowed the sender but their mail still isn’t arriving.”
Allowing only turns off the spam-content checks. If mail still doesn’t come through, the message is likely being stopped earlier, at the connection level. Common causes:
None of these are fixed by allowlisting on your end — they usually need the sender to correct something. Check your panel’s Log Search (sometimes called the incoming log or delivery queue) to see exactly why a specific message was refused, then share that reason with your provider or the sender.
“The message is sitting in quarantine — do I need a rule?”
Not necessarily. You can release an individual message from quarantine directly from the log/quarantine view, and most panels offer to allow that sender at the same time. That’s often quicker than building a rule.
“My filtering rule isn’t catching the mail.”
The most common cause is matching on the header From when you should be matching on the envelope Sender (or vice versa). Open the message’s raw headers to confirm the exact value, and consider adding a second condition so the rule is both accurate and specific.
Keep your allow list tight. Every entry is a small hole in the filter, so allow only what you genuinely need, favor specific addresses over whole domains, and review the list from time to time.