Hello Paul,
Really interesting (and puzzling). Perhaps something specific to the OS ?
Here my configuration:
14 Jun 00:13:01 - [info] Node-RED version: v0.18.4
14 Jun 00:13:01 - [info] Node.js version: v8.11.1
14 Jun 00:13:01 - [info] Windows_NT 10.0.17134 x64 LE
What happens if you fix the destination ports in both UDP output nodes ? Like below for instance ?
the code I test (just in case):
[{"id":"1b03db00.66de75","type":"tab","label":"Flow 3","disabled":false,"info":""},{"id":"c9229d.46030d6","type":"inject","z":"1b03db00.66de75","name":"Send Ping","topic":"","payload":"Ping","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":422.50001525878906,"y":290.00000762939453,"wires":[["53f754c1.c89fbc"]]},{"id":"4394e591.ad717c","type":"udp out","z":"1b03db00.66de75","name":"Send from port 3000","addr":"","iface":"","port":"","ipv":"udp4","outport":"3000","base64":false,"multicast":"false","x":942.5000152587891,"y":230.00000762939453,"wires":[]},{"id":"865c646e.e911d8","type":"udp in","z":"1b03db00.66de75","name":"Listen on port 3000","iface":"","port":"3000","ipv":"udp4","multicast":"false","group":"","datatype":"utf8","x":132.50001525878906,"y":130.00000762939453,"wires":[["c9b498fe.0b81f8","5c9bc1e6.6d33f"]]},{"id":"c9b498fe.0b81f8","type":"debug","z":"1b03db00.66de75","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","x":412.50001525878906,"y":90.00000762939453,"wires":[]},{"id":"5c9bc1e6.6d33f","type":"delay","z":"1b03db00.66de75","name":"Delay 5s","pauseType":"delay","timeout":"5","timeoutUnits":"seconds","rate":"1","nbRateUnits":"1","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","drop":false,"x":373.50000762939453,"y":164.00001430511475,"wires":[["53f754c1.c89fbc"]]},{"id":"d68c1e8d.fdd5a","type":"inject","z":"1b03db00.66de75","name":"Send Pong","topic":"","payload":"Pong","payloadType":"str","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":422.50001525878906,"y":730.0000076293945,"wires":[["ddce1a7b.0987d8"]]},{"id":"357fdcf3.b41de4","type":"udp out","z":"1b03db00.66de75","name":"Send from port 3001","addr":"","iface":"","port":"","ipv":"udp4","outport":"3001","base64":false,"multicast":"false","x":862.5000152587891,"y":670.0000076293945,"wires":[]},{"id":"c812eac6.7eb388","type":"udp in","z":"1b03db00.66de75","name":"Listen on port 3001","iface":"","port":"3001","ipv":"udp4","multicast":"false","group":"","datatype":"utf8","x":132.50001525878906,"y":550.0000076293945,"wires":[["f2f3978.792d468","189ce106.e5af9f"]]},{"id":"189ce106.e5af9f","type":"debug","z":"1b03db00.66de75","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","x":412.50001525878906,"y":490.00000762939453,"wires":[]},{"id":"f2f3978.792d468","type":"delay","z":"1b03db00.66de75","name":"Delay 5s","pauseType":"delay","timeout":"5","timeoutUnits":"seconds","rate":"1","nbRateUnits":"1","rateUnits":"second","randomFirst":"1","randomLast":"5","randomUnits":"seconds","drop":false,"x":422.50001525878906,"y":610.0000076293945,"wires":[["ddce1a7b.0987d8"]]},{"id":"53f754c1.c89fbc","type":"function","z":"1b03db00.66de75","name":"To Endpoint B on port 3001","func":"msg.ip = \"localhost\";\nmsg.port = 3001;\nmsg.payload = \"ping\";\nreturn msg;","outputs":1,"noerr":0,"x":662.5000152587891,"y":230.00000762939453,"wires":[["4394e591.ad717c"]]},{"id":"ddce1a7b.0987d8","type":"function","z":"1b03db00.66de75","name":"Reply with Pong","func":"let message = {\"ip\":msg.ip, \"port\": msg.port, \"payload\": \"pong\"}\nreturn message;","outputs":1,"noerr":0,"x":622.5000152587891,"y":670.0000076293945,"wires":[["357fdcf3.b41de4"]]},{"id":"d07d24f8.f12dc8","type":"comment","z":"1b03db00.66de75","name":"Endpoint A","info":"","x":102.50001525878906,"y":90.00000762939453,"wires":[]},{"id":"a4e9e294.cc4f8","type":"comment","z":"1b03db00.66de75","name":"Endpoint B","info":"","x":102.50001525878906,"y":510.00000762939453,"wires":[]}]
