Port forwarding UDP port

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    I have an instance of NX 4.3.24 running (as a server) on Ubuntu 12.04 LTS behind a router. I’m forwarding TCP on a high-numbered port on the WAN side to port 4000 on the LAN side, and this works fine. But the default config for UDP (“to improve multimedia performance”) on new connections seems to be a randomly selected port between 4011 and 4999. So, three questions:

    1) How can I check what UDP port a running NX server is listening on by default (or does it wait until an inbound connection is negotiated via TCP before setting up the UDP port)?

    2) When a new connection is defined in NX client and UDP is enabled, the UDP port gets assigned a seemingly random value (the fallback range is always 4011-4999). How is that value determined, and can it change on its own after the connection is defined?

    3) Since the UDP stuff falls back to negotiating a port within the specified range if the initial UDP connection fails, woild I need to forward the entire range of UDP ports (4011-4999) from WAN to LAN to ensure that this works correctly? Or is it sufficient to just forward the single UDP port I know I’ve set up on the client?

    Thanks very much in advance,



    1) On the server side this port is taken from a range set in config key.

    #UDPPort 4011-4999

    It can be set to just one value instead of the range but in that case only one session will be able to use UDP. If it’s a range, a port is selected randomly at session start.

    2) You can set it in the player GUI to use a specific port instead of a random one from range. However it’s a global setting, so all sessions will use the same. In that case, only one session will be able to use UDP.

    3) It will be sufficient to forward single UDP port set up on both sides, it’s a separate setting in client and in server and both have to be forwarded. Otherwise the whole range has to be forwarded.

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