Spam Experts Help

Manage Attachment Restrictions

The Attachment restrictions page allows you to configure which email attachments to allow and which to block.

In the Domain Level Control Panel, select Email restrictions - Attachment restrictions the Attachment restrictions page is displayed:

The following restrictions can be configured:

Restriction Description
Blocked Extensions

Messages that have an attachment with any of the selected extensions will be rejected.

You can add new extensions to those listed using the Add new extension feature.

Disallowed release extensions

Email users will not be allowed to release messages that contain attachments with the selected extensions.

You can add extensions to this list using the Add new extension feature.

Restriction options
  • Block password-protected archive attachments - If enabled, blocks messages with password protected attachments like zip files.
  • Block potentially unwanted attachments - If enabled, rejects attachments that are considered dangerous or unwanted. For example, compressed executable files (e.g. UPX packers), password tools, network tools, peer-to-peer clients, remote access applications, system tools, spying tools and documents containing scripts.
  • Block attachments that contain hidden executables - If enabled, ZIP, TAR, GZIP, BZIP2 and 7Z archives (other than those compressed with deflate64) are checked and the message will be rejected if the archive appears to contain an executable.
Additional restrictions

Message link size limit (in bytes) - This option restricts the amount of data that is downloaded per message. Links in messages to executable files that would be blocked as attachments are followed and the content is checked against an anti-virus database.

Maximum MIME defects - Messages that are sent with standard email clients have no defects, whereas spam messages are often generated with poorly developed software and have many defects. Normally we reject messages with defects but if you have a need to receive defective messages, you may set a limit or disable this check. If the defective messages come from a single sender, it would generally be better to either convince the sender to fix their software or whitelist that sender.

Scanned link extensions

If the Message link size limit is set (above), then links in messages to files with the selected extensions will be scanned for viruses and other malware.

You can add extensions to this list using the Add new extension feature.

Default (inherited) Blocked Extensions Default (inherited) Scanned Link Extensions


.adp .btm
.bat .cmd
.btm .cpl


.cmd .exe
.com .lnk
.cpl .msi
.dll .pif
.docm .prf
.exe .reg
.hta .scr
.ins .url
.isp .vbs