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Networking over internet

When, for instance, activating a special event callsign it is possible to network multiple stations over the internet.

Please be aware that a geographically distributed station is, with only a few exceptions, against the rules in all contests


The most secure way to do this is to rely on a VLAN (virtual LAN) software. There are several available such as:

LogMeIn Hamachi

Each VLAN solutions have their own particular set up which is covered in their respective documentations.
With a VLAN solution, all configurations are the same as when operating in a regular LAN.

Port forwarding

If you are less worried about competitors or government agencies listening in on your contest data,
it is possible to route the traffic directly over the internet using port forwarding at the server.

Important security notice: This solution is not without risk. It offers no security or authentication.
Any station running the same contest configuration, knowing the URL or IP address and IP port of the
server can connect to the server station. There are no means to disconnect a station by force.

With a port forwarding solution, the following must be observed:

  • Only one of the stations should be configured as the server.
  • "Connect as client" should not be checked and "UDP network broadcast" should only be enabled if it is
used to communicate with another client on the same LAN.
  • The PC acting as server must have a fixed LAN IP address. This is done either by manually configuring the
PC to use a fixed LAN IP address, or by setting up the router in the server's LAN to to always allocate
the same IP address to it.
  • The internet connection used by the server PC must either have a fixed public IP
address or use dynamic DNS. Otherwise clients will not be able to reliable connect over the internet.
  • The server's IP port (default 9888) must be forwarded to the internet by configuring the router
connecting the server to internet. Only TCP traffic should be forwarded. UDP traffic
is broadcast and should only be used locally.

Example configuration for server for networking over internet

Example of port forwarding UI in router

  • All other PC in the multi-station set up should be set up as clients.
  • Over the internet, "Server IP" is either the public IP address of the server's internet
connection (e.g. or the dynamic DNS address (e.g. Clients connecting
over the internet does not have to enable UDP networking and should not enable a server.
  • A client may connect via UDP if it is on the same LAN as the server or a "master client".
A "master client" is a client that connects to the server using the "connect as client" option in
the networking set up panel. A "master client" can act as a UDP gateway which means that if
several computers on a LAN are part of the same multi station set up but the server is located
elsewhere, only one computer in that LAN needs to connect as a client and the rest can use UDP.

Example configuration of client for networking over internet

  • In a multi-station setting it is recommended to enable Options->Networking->Don't allow QSO logging if operator isn't logged
  • Make sure Options->Enable network is checked.