Network problems in Windows?

Question

Computer networks

Hello. Help me please. I don't know what to do anymore. Weird networking issues occur intermittently ( Windows Server 2008 R2 ).
There is a router with a white IP, it is connected directly to the provider via Ethernet, it distributes the Internet for the home network. The problem computer is connected to the router via cable.
Problems begin gradually, although there are no external manifestations of this. First, the pages start to open for a long time. Then they do not open completely (images, CSS, etc. are not loaded). At the same time, an increasing percentage of pings gradually begins to disappear . Eventually pings stop going anywhere but the router ( 192.168.1.1 ) and only the router's control panel can be opened from Web pages.
At the same time, already open Gmail or Google+ pages somehow work.
Turning off the torrent client allows you to solve the problem for a short time (from a couple of minutes to an hour). The same can be said about overloading the router, and juggling network connections in Windows. Overloading the system, in principle, saves, but also not forever. This was not the case a month ago. A week ago, the problems began after 2-3 days of work. Now it is often impossible to work even a few hours.
This problem happened before, a couple of months ago. Several days were spent looking for a solution, but without success. After that, a rollback was made for 2 weeks. Not a perfect solution, but saved for a while. Now it's back.
Key moment, due to which I ruled out any possibility of a hardware origin. The target server is running multiple virtual machines. In fact, these machines are on the same subnet as the host (problem) and use the same network card. So, they don't have these problems at all. All other devices on the home network are also fine.
Of the moments that may seem interesting: Hamachi is installed , the server has the Hyper-V role , the paging file is disabled. Stopping these services did not solve the problem, there is no lack of memory. Disabling all possible services and killing processes did not give any results. Rebooting, too.
If necessary, I can provide the necessary hardware and software configuration. But it seems to me that this is useless, because. the problem is conceptual, and with the same settings everything can work fine.
The impression is that the system begins to lack some internal resources to open connections. But apart from this theoretical assumption, I have nothing.
I call for help. Or at least tell me where to go to identify the source. Or at least something, I don't have any thoughts about it anymore... Just please don't suggest reinstalling Windows.

Answer 1

If it appears along with torrents, then you may be hitting the limit of half-open connections.

Answer 2

IMHO the most correct solution for a host server is at least 2 network cards. The first is for server management, the second is for virtual machines. Moreover, on the map with virtual machines, I remove all clients, services and protocols so that no one else can connect to this network. Well, you need to use normal network cards, I decided to save some money, I got cheap gigabit TP-LINKs, Hyper-V was very clumsy friends with them, I changed them to Intel ones - everything worked as it should. And sometimes you have to use 3 or more network ones if the network is complex, so I don’t advise you to hang everything on one network card.

Answer 3

Maybe one of the network nodes is fragmenting packets incorrectly? Try to compare MTU on interfaces. If one of them is less than the others, sniffer the traffic on this node.

Answer 4

Or maybe it's all about the Trojan? There was such a thing in one office, the Trojan ate the entire NAT and everything died in the external environment.

Answer 5

and netstat -an what says when problems appear?

Answer 6

Windows utilities for diagnosing and configuring a network

Answer 7

It may indeed be the MTU. Check, just in case, for some reason Windows itself sometimes sets it to 1540.
man openvpn tells me:
MTU problems often manifest themselves as connections which hang during periods of active usage.