[Mr. Lim]

Originally Posted by Alan Anderson

The problem is that the roboRIO itself doesn't connect to the FMS, and it can't know whether or not to be a DHCP server until after it is already talking to the Driver Station.

I can't think of a reliable way to have a DHCP server decide to be active only when the FMS is not present. There are too many chances for it to be running before the DS has made the FMS connection. My preference would be for a separate physical device in the Ethernet tether between DS and robot bridge.

But the RoboRIO does get its IP address from the FMS's DHCP server. I think it may be possible (although I have personally never done it) to configure a DHCP server on the RoboRIO to only hand out leases if there isn't already a DHCP server on the same network. If it detects another DHCP server (i.e. the FMS's) on the network it simply won't do anything, and let the existing (FMS's) DHCP handle everything.

Redundant DHCP servers that are configured for failover have been around for a long time. Maybe this is an approach worth exploring:

https://kb.isc.org/article/AA-00502/...-Failover.html

Also, if the RoboRIO's DHCP server hands out a bunch of leases BEFORE connecting to the FMS, would this necessarily be a bad thing? I'm not sure there is a downside. All the devices would get proper 10.te.am.zz IPs, and assuming mDNS is still configured, everything should be addressable by hostname, even if the FMS doesn't know everyone's IP address via DHCP.