Block mail by attachment file type
Add dangerous file extensions to the block list so the filter rejects the whole message, and learn why the trusted list cannot override it.
Malware scanning inspects what is inside a file. This page blocks by file extension, whatever is inside.
Before you start
- The domain is live. See Point MX through the filtering gateway
- Your own list of file types to forbid, if you have one
It rejects the message, it does not strip the file
The message is rejected whole, and never reaches quarantine
A message carrying an attachment with a blocked extension is rejected whole: the recipient sees nothing, and it does not land in quarantine to be released.
Tell your senders before you block an extension they actually use at work. They do get a delivery failure notice — but only if they read it.
Add an extension
Go to Email Security → Attachment filters.
Type it in
The FILE EXTENSION TO BLOCK input has a fixed . on its left. Type the part after the dot, then
click Add to block list.
| You type | Result |
|---|---|
exe | ✅ blocks .exe |
.exe | ✅ the extra dot is dropped, still .exe |
EXE | ✅ lower-cased automatically |
tar.gz | ❌ letters and digits only, no dot in the middle |
documents | ❌ ten characters maximum |
An extension already on the list is reported as a duplicate, not added twice.
Or click a suggestion
The Quick suggestions row offers common dangerous extensions — clicking one adds it immediately, with no confirmation.
The row shrinks by itself: anything already blocked disappears from it. One or two entries left means you have blocked most of the common types.
Review and remove
The Blocked file extensions table lists every extension in force, with a bin button.
Click the bin and confirm. Messages carrying that file type pass again — still malware-scanned, just no longer blocked on the name.
The trusted list cannot override this
The order is fixed:
| Order | Mechanism |
|---|---|
| 1 | Malware scanning |
| 2 | Attachment filter (this page) |
| 3 | Trusted senders (whitelist) |
| 4 | Blacklist |
A sender on your trusted list still cannot send you a blocked file type.
There is no per-sender exception: removing an extension from the block list removes it for everyone.
Check your work
The list takes effect immediately.
From an outside address, send a message carrying the extension you just blocked: the recipient gets nothing, and the sender gets a delivery failure notice.
Confirm in Email tracking: the row must read Rejected. Delivered means the extension you entered does not match the file's real one — check the filename.