Network Port Usage

Open Cobalt uses a number of network services that you may have to poke holes in your firewall for or make changes to the network configuration, depending on how strict your network security is and the services of Open Cobalt that are actually used. For more detail, check the rest of the Admin guides.
  • If you want to make your internal spaces available to external peers, the configuration is more complex and you will need to look at the router configuration documentation
  • Port numbers listed are for default configured in services and may change.
External Service and Port Usage
These are services that an Open Cobalt installation may try to connect to on the greater Internet.
 Ports Direction Usage
 53 outgoing Jabber-based chat and Space Directory clients try to use the Google caching DNS service at or Reconfigurable in browser config. Also used to do DNS based Service Discovery when looking for a dispatcher.
 TCP 80 outgoing Version check, ad-hoc space registry, web space load
 LDAP TCP 1389 outgoing Space Directory access. Reconfigurable in General Preferences.
 XRFB/HTTP TCP 5899 outgoing Xrfb/VNC application service, control protocol. Reconfigurable in General Preferences.
 VNC TCP 5900-5930 outgoing Xrfb/VNC application service, interaction protocol
 XMPP TCP 5222-5223 outgoing Jabber-based chat.
 TeaTime TCP
 6900-6909 outgoing P2P connection to external routers and spaces
 TeaTime TCP 6900-6909 incoming P2P connection from external peers to internal router/space. See router configuration documentation

Internal Usage
These are the services that Open Cobalt may try to utilize on the local network.
 Application Protocol Ports  Usage
 DNS UDP/TCP 53  Many services will use the DNS server the OS hands it, usually some internal one that is given to the OS via DHCP
  Discovery protocol to find a UPnP Internet Gateway Device (IGD) router for the automatic port forwarding configuration of the Open Cobalt message routing. Multicasts on address Also used to find non-local dispatchers on the same network segment.
 CRQT UDP 43215  Private discovery protocol for the spaces. It broadcasts on so it shouldn't go outside the local net.
 device dependent
  If it finds a UPnP IGD then it will use the SOAP based UPnP protocols to try to configure an external port forward.