Plugin only works if home bridge is on same subnet as vacuum?

[jcapayne]

Homebridge is on subnet A, vacuum is on subnet B. Kept getting errors like:

Apr 24 16:34:10 sconsetpi homebridge[6170]: [4/24/2023, 4:34:10 PM] [Marvin] [Model=unknown] ERR connect | miio.device, next try in 2 minutes | Error: Could not connect to device, handshake timeout
Apr 24 16:34:10 sconsetpi homebridge[6170]: [4/24/2023, 4:34:10 PM] [homebridge-xiaomi-roborock-vacuum] This plugin threw an error from the characteristic 'On': Unhandled error thrown inside read handler for characteristic: Could not connect to device, handshake timeout. See https://homebridge.io/w/JtMGR for more info.

tcpdump showed a UDP packet being sent but no response (TTL of 64, so it should have reached). IP connectivity between the subnets was fine (ping works). miiocli cloud list showed the IP and the token.

miio-vacuum said

 INFO  Attempting to inspect X.X.X.X
 WARNING  Could not find device

I moved homebridge into subnet B and it instantly worked in home bridge and miio-vacuum. Is this expected? Any reason why it couldn't work cross-subnet?

[afharo]

I found this: https://stackoverflow.com/questions/28163422/send-udp-message-outside-of-subnet

It might be relevant