Had a strange issue run past my desk this week, figured I’d share the fix if anyone has similar in the future…
So we have a few Panasonic BB-HCM581 cameras that for some reason or another decided to go to factory reset default. When they would do this, they would show up in DHCP for a short period of time, then disappear. They would also not be pingable/reachable from that DHCP address. After troubleshooting every possible DHCP issue known to MS, I ended up wiresharking the actual camera network traffic and hosting small dhcp server on the same box to see what was going wrong.
It turns out, Panasonic cameras when set to factory default, grab a DHCP ip address only long enough to detect what subnet and ip range they are on. The camera then drops its dhcp ip (dhcp release) but does not inform the dhcp server. This leads the dhcp server to believe the camera is still using this ip, even after its released it. The camera then uses the learned subnet range, and tacks itself onto that range with an ip of .253.
For example:
- You reset a panasonic camera to factory default. The IP range the dhcp server is providing to that cameras network is: 192.168.0.50 to 192.168.0.150 with a subnet of 255.255.255.0
- The camera will request an ip from the dhcp server (dhcp request packet), and the dhcp server will reply and provide it a usable address (dhcp ack/reply packet). Lets say it provides an ip of 192.168.0.50 255.255.255.0
- The camera will accept that packet, look at the subnet: 192.168.0.x 255.255.255.0, and then drop its dhcp assigned ip (dhcp release) without informing the dhcp server
- The dhcp server at this point assumes the camera is using 192.168.0.50 and all is well, however if you try to ping 192.168.0.50 or reach it in a browser, you’ll get no response.
- So here’s the tricky bit, the camera, having learned what subnet range its on (192.168.0.x 255.255.255.0) will then give itself an ip of .253, in this case its ip will become: 192.168.0.253
- You’ll find if you try to reach out to 192.168.0.253 after all the above has taken place, the camera will be available and asking for first time setup information! Go ahead and give it a static ip, so you never have to deal with these shenanigans ever again.
Hope this helps anyone that has similar issues, Panasonic manuals and docs were no help on this one.