Device unreachable — step by step#

Symptom: the platform shows no data from a device, and the device doesn't answer from the Octave device.

This page walks the troubleshooting ladder for a real example: the BESS at 192.168.1.60 on a RevPi's eth1. Swap in your own device and interface.

1. Link — Ethernet Link#

Run Ethernet Link for eth1. It must report a link.

• No link → check the cable, the switch port lights and the switch's power. Swap the cable. On a RevPi, make sure the cable isn't in eth0 by mistake.

2. Address — Network Overview#

Run Network Overview. Under Interfaces, eth1 must show the secondary IP, e.g. 192.168.1.17/32.

• Missing or wrong → fix it on the Configuration page (Scenario 3).

3. Route — Route Test#

Run Route Test for 192.168.1.60.

4. Neighbour — Network Overview → Neighbors#

After a ping attempt, look for 192.168.1.60 in the Neighbors table.

• MAC shown, REACHABLE / STALE → the device is on the cable. Go to step 5.
• FAILED → nothing on eth1 answered for that IP. Check the device's real IP on its display, check that it's powered, and check that it's on the Octave switch.

5. Reachability — Connectivity#

Run Connectivity for 192.168.1.60 with Also run ARPing ticked and Interface for ARPing = eth1.

• Ping ✅ → go to step 6.
• Ping ❌, ARPing ✅ → the device ignores ping. Go to step 6.
• Both ❌ → same as FAILED above.

6. Service — Port / Service Scan#

Run Port / Service Scan for 192.168.1.60 with the Modbus preset.

• open → the network is fine. The problem is in the Modbus settings: unit ID, register map, or the device allowing only one client. See Ping works, Modbus doesn't.
• closed → Modbus TCP is disabled on the device, or uses another port.
• filtered → a firewall on the device or in between.