OMV "blocks" Win10 Network

It is definitely a wrong network setting you are using on the OMV system but without telling us what your settings are, no one can help.

Zitat von morph8000

what infos do you need?

network settings. I don't care how you present them.

Zitat von morph8000

Or is it better to update to Version 4.x?

Normally I would say it is better to upgrade to OMV 4.x, I don't know how that upgrade will work on a BPi.

I don't see anything wrong there. Rsync is definitely not the problem. I assume your router's IP address is 192.168.0.1? What do you mean the BPi is the "first" device on the network? Do you have the dnsmasq plugin installed on the BPi?

Zitat von morph8000

I disabled it. IPv6 was disabled before, now I set it to dhcp.

No disable IPv6, your network is using IPv4, and in the first image Hostname is set but not the Domain name, the domain name is whatever you're using on your windows machines, e.g. workgroup.

Zitat von morph8000

added Domain-name "workgroup",

Is that what your W10 machines are set too? I used workgroup as an example.

This could also be the switch, network cable, network adaptor on the w10 machines, have you run the network troubleshooter, have you looked at updating the network driver on the w10 machines.

...or the DHCP configuration.

The OMV server has a fixed IP. 192.168.0.50

What range of addresses does the DHCP server give out? Is 192.168.0.50 in the range?

Zitat von morph8000

2 PCs with different Networkcards and cables both have the same problem. So I dont think, switch, cable or something is the problem.

Ok, but it's not an OMV problem either, this is something related to your network, I have known switches appear to work, only to find out with some testing that the switch was failing on certain ports and therefore creating network problems. Running the network troubleshooter will usually give up some information.

Zitat von morph8000

DHCP range is 140 devices, so ...50 shouldn't be a problem. 2 PCs with different Networkcards and cables both have the same problem. So I dont think, switch, cable or something is the problem.

I agree that it shouldn't be a problem. But that doesn't help if it is a problem. If the DHCP server is trying to give out IP numbers that are used already you get exactly the problems that you reported.

If the Windows boxes aren't looking at the OMV system for dns and none of the systems have duplicate IP addresses, I have no idea how this could happen without bad hardware and/or something weird with the router.

Zitat von morph8000

Resetting network, the suggested solution from win10

I have been working with Windows machines for longer than I can remember and that it not necessary!

All this is related to your network, as @Adoby has said it could have something to do with DHCP, so what is the DHCP range on your router it should have something like 192.168.0.xxx to 192.168.0.xxx (xxx being number/s).

I suggest that you go over ALL your devices and figure out exactly what IP they use, where they got that from and how you can make sure it doesn't conflict with other devices. It might even be a good idea to write it all down on a piece of paper or in a file somewhere. And/or put the info on stickers on each device.

Using fixed IP only on network equipment, printers, media players and servers is a good idea. Let the rest use DHCP.

It seems you or somebody else have assigned the same IP to more than one device. It may be from having more than one DHCP server or from you not keeping track of the IPs in use and the range(s) of the IPs the DHCP server(s) give out.

One very simple method is to use some network scanning software to figure out what IPs are in use. Also login to routers, access points, repeaters and other similar devices to see if the have a DHCP server active. It might be helpful to disable all DHCP servers except one.

Your description that some IPs work but other doesn't seem to confirm (even prove?) that you use the same IP on multiple devices.