mirror of https://github.com/ArduPilot/ardupilot
75 lines
2.5 KiB
Markdown
75 lines
2.5 KiB
Markdown
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# UDP Proxy
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This is a tool to do UDP proxying, particularly for MAVLink
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connections. It is useful when operating both a ground station and
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aircraft on network links that don't have a public IP address.
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# Functionality
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udpproxy opens two listening UDP ports. When it has a connection on
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both ports then it will forward packets between the ports. This allows
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your GCS to connect to one of the ports and your aircraft to connect
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to the other port. The GCS and aircraft will be able to communicate,
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despite both not having public IP addresses.
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# Why not a VPN?
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udpproxy is an alternative to using a VPN for communication between
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the aircraft and the GCS. The reason for not using a VPN in flight is
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VPNs typically have a high reconnect time, and often add significant
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latency. This poses an issue for aircraft control as you may lose the
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ability to control the aircraft for minutes if there is a short
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network outage. Using udpproxy minimises the time for the link to
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re-establish after a network outage.
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# Disadvantages
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The main disadvantage of udpproxy is that it offers no security. If
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someone knows that UDP ports and host you are using then they could
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connect to your aircraft and control it. The risk can be reduced by
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enabling MAVLink2 signing which allows you to ensure that nobody can
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control the aircraft without knowing the signing key.
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You can also reduce the risk by using firewall rules on the computer
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to run the proxy on to only allow connections from the IP ranges you
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known you will be using.
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# Building
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Just run 'make' command
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# Usage
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Basic usage is:
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udpproxy PORT1 PORT2
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this will listen on both PORT1 and PORT2. You should then make an
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outgoing UDP connection from both GCS and aircraft to those ports, one
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to each port.
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Adding the -v option tells udpproxy to display information about new
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connections and shows transfer rates which are useful for diagnostics.
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You should run udpproxy on a computer with a public IP address.
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# Keeping it running
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You will typically want to keep udpproxy running for long periods
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without having to keep a shell open on the computer running the
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proxy. An example script which starts it under GNU screen and thus
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allows you to monitor the connections and automatically restart them
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is provided in this directory.
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# Connecting
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To connect from mavproxy to your proxy just add this to the
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mavproxy.py command line:
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--out AA.BB.CC.DD:PORT1
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where AA.BB.CC.DD is the IPv4 network address of your proxy.
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To connect from MissionPlanner use the "UDPCL" option, and enter the
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IP address and port number of the proxy.
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