Can zoneminder "destroy" eth connection?

[danielmalaga]

Since I have a new mini-computer connected to the switch to which the cameras are connected, after some days the eth connection breaks down. I can ping the switch, but not the cameras behind the switch. Before the eth0 connection breaks down ZoneMinder and all cameras work perfectly.

As I cannot find any explanation for what happens I ask if it is possible that zoneminder "destroys" the eth connections?

Details:

After a few days of running, zoneminder suddenly loses connection to the cameras because they are not reachable in the network anymore. Except of zoneminders messages (Failed to capture... Network is unreachable... unknown error occurred...) I cannot find anything in /var/log/messages about network errors. I can ping the switch, but not the cameras. So "something" in the network is not working.

Disconnect-reconnect eth0/unplug-replug cables/rebooting PC/completely disconnect/reconnect PC, switch and cameras from electricity doesn't help, the IP's of the cameras remain unreachable.

BUT when I simply plug the eth cable from the switch to the laptop (on which I run ZoneMinder before) all cameras on this network are immediately reachable AND when I then plug back the cable to the PC all of a sudden everything works again here, too. Actually this is the only way to get the eth connections work again...

Software:
on the new mini PC: ZoneMinder v1.36.33 on OpenSuse 15.5
on the laptop: v1.36.11 on OpenSuse 15.3
only one network is defined with a fixed IP address (no internet connection, no WiFi)

Hardware:
mini PC: Intel i7 with 36GB RAM
laptop: intel i9 with 36GB RAM
switch: Netgear GS308PP
cameras: Reolink RLC810A
cameras are connected via cable to the switch, the switch via cable to the PC (or laptop)

The cameras and the switch run perfectly during a long time (sometimes several months uptime) on the laptop, the problem occurs only on the new PC with the new ZoneMinder subversion, with the same cables etc.

Any ideas?
Thanks for your help!

[dougmccrary]

That's pretty weird.

Have you replaced the PC cable? May be failing, and plugging/replugging/moving it make it come good. For a while.
I had (hopefully fixed) a similar problem with a wired AP failing recently.

[danielmalaga]

It is really weird

Unplugging/Plugging itself doesn't help. The - for me - crazy thing is, that plugging it into the laptop and then back to the PC makes the change.

It's definitively not the cable, as it works perfectly with the laptop...

[dougmccrary]

I'm afraid that is an invalid assumption.
Good luck.

[Magic919]

I can't believe ZM has any influence here.

Can ping the switch, but not the cameras is just wierd. I'm assuming the cameras are attached to said switch.

[danielmalaga]

I can't believe it neither, but as I am no computer expert and found no other explanation, also not on the OS maillist, I dared to ask here, because - maybe... you never know...

I must correct myself: I cannot ping the switch, as this is an unmanaged switch that has no own IP; what I can ping is eth0 by its IP

[Magic919]

I can't think of anything that would happen that would persist over reboot of the server, TBH.

Pinging the server's address from the server, just suggests it thinks its interface is up. (Unless you mean you can ping the server from elsewhere.)

[Andyrh]

When the error happens:
1. From another PC
a. ping the ZM server
b. ping a camera
2. From the ZM server ping the default gateway

If 1.a fails, but 1.b works then the problem is not the cameras
if 2 and 1.a fail then the problem is with the ZM server or the switch port for the ZM server
If 1.a or 2 works the problem might be the switch

The goal is the thin out the possible problems to narrow the list to something manageable. Without more information I would guess you have a port problem, either the switch or the PC. Another quick test is to move the ZM server to a different switch port.

[danielmalaga]

SOLVED

So, as I thought, the problem was not zoneminder
Although in this case it is offtopic to zoneminder I describe it here, in case somebody else experiences similar...

The problem was that the (Reolink)-Cameras were set to use DHCP, but there is no DHCP-server on my pc. The cameras are also set to reboot every Sunday night at 02.00h. After they want to reboot they don't find the connection anymore and thus do not finish the reboot. Only connecting them to another computer that has a DHCP-server running made them finish the reboot immediately.

The solution was to set the camera's IP to "STATIC" instead of DHCP. That's all.

(I though they were static as I gave them a fixed IP which worked - until reboot. I had not seen the select-box static/dhcp)