Developers Documentation



301 error for file:

User Tools

Site Tools

Protocol Filter

The Protocol Filter feature is used to block unwanted traffic from your network. The feature is commonly used to make sure employees, students or end users are using their Internet access for its intended productive use. The filter can block dozens of different protocols, including:

  • peer-to-peer traffic
  • VoIP and Skype
  • streaming audio and video


If you did not select this module to be included during the installation process, you must first install the module.

You can find this feature in the menu system at the following location:

Gateway|Protocol Filter|Protocol Filter Configuration



By default, the protocol filter displays the full list of protocols and the status of each one. Since there are well over 100 protocols defined, you can filter the display by type:

  • Document Retrieval
  • File Types
  • Instant Messaging/Chat
  • Mail
  • Monitoring
  • Networking
  • Peer-to-Peer
  • Printing
  • Remote Access
  • Security Protocols
  • Streaming Audio
  • Streaming Video
  • Time Synchronization
  • Version Control
  • Video Games
  • VoIP
  • Worm/Virus

At any point, you can click on or to set your Protocol Filter policy for your network. When blocked, all access to and from your network will be blocked by the ClearOS gateway.


In some circumstances, you may want to allow specific systems to bypass the protocol filter system. For example, you may want to block voice-over-IP (VoIP) traffic for your entire network, except for the dedicated VoIP/PBX server. In these circumstances, you can add IP addresses to the protocol filter bypass configuration:

  • Click on the Bypass
  • Specify a Nickname (for example, voip_server) and the IP address
  • Click on


The protocol filter can slow down network performance!

If your connection to the Internet is faster than 5 Mbps, we do not recommend using the protocol filter at this time. You should also be aware that not all protocol filter rules are created equal. Some rules have little effect on performance while others can have a significant impact.


content/en_us/6_protocol_filter.txt · Last modified: 2018/07/20 18:53 by pbaldwin