Robot router uses symmetric NAT

Where this comes from

This is the page <seyd-connect-error> links to for the diagnosis class robot-symmetric-nat. The class is chosen by classify() in @seyd/web from the robot’s NAT report and the failure reason; see Reachability for how the report is built.

Seyd’s STUN probe found that the robot’s router allocates a different external port for every destination. The public address the robot announces is only valid for the cloud that helped it discover it, so a browser connecting from anywhere else hits a closed port. Port mapping was not available to fix it.

What to do

1. Enable UPnP, NAT-PMP or PCP on the router. Seyd asks the router for a mapping itself on every start and network change, installs the pinhole and announces the mapped address as a portmap candidate. On most consumer and 4G routers this is one checkbox. This is the fix we recommend, and the one field testing settled on for robots behind 4G routers.
2. Or forward the port once by hand: UDP <quic_port> (4433 by default) on the router to the robot’s LAN address and the same port. Give the robot a DHCP reservation so the address does not move.

After either change, restart the daemon or wait for its next re-announce; the console shows the new candidate and the prober’s verdict before anyone connects.