Internet connection drops every hour

Question

I recently built a new desktop computer, which works fine except for connecting it to our network. I have an ethernet cable directly connecting my modem to my computer, and around every hour or so, the internet connection cuts off not just for me, but for all devices in my network. My computer uses Windows 10.

When my internet cuts off, it doesn't completely cut off. What seems to happen is that on my end (desktop computer connecting directly to the router), the DNS server is unable to be reached. This is the problem that Windows Problem Solver is giving me, and what I've been able to confirm for myself, as IP addresses can be reached but plain web addresses cannot be. In addition, it kicks every device using WiFi off the network. Our WiFi network can still be detected by these devices, but they are unable to connect to it. When the modem is turned off and on again, it works fine again for an hour until the same problem occurs.

Some things I've tried and established:

• The ethernet cable should not be the issue here. Before building my new computer, I used a laptop which I also directly connected to the modem using the same cable I do now, and we haven't had any problems like this for 1.5 years.
• My new PC being connected absolutely has something to do with this. If the modem is reset while my new PC is not connected, no problems occur.
• On the other hand, disabling and reenabling the Ethernet connection from my PC after it has already connected to the modem does not affect the 1 hour timer.
• My new PC is the only device connected to our network that is running Windows 10.
• Performing a factory reset on the modem did not appear to have any effect.
• I'm currently having my Ethernet connection use Google's DNS servers (8.8.8.8 and 8.8.4.4). When the network cuts off this does indeed allow me to continue browsing, so it does appear to have something to do with DNS servers. Similarly, applications like Skype still function normally. This isn't always the case though, as sometimes the modem just seems to completely lose all internet connection causing me to be unable to use it at all, though this tends to happen longer than an hour after resetting the modem.
• Changing the WiFi channel doesn't do anything (though I guess this was to be expected).
• Updating my version of Windows 10 didn't do anything. This was a decent possibility since my installation of Windows 10 came from a disc that was burned half a year ago. My installation of Windows 10 has also not been activated yet, but I'd like to leave that until I have managed to fix this problem.
• My modem has an ECO function which causes the modem to be shut off at specific time intervals, but this is disabled.
• According to the manual, our modem automatically performs updates. I haven't found a way to manually perform an update or check the version of the modem.

ipconfig /all gives the following information.

Ethernet adapter Ethernet:

   Connection-specific DNS Suffix  . : home
   Description . . . . . . . . . . . : Intel(R) Ethernet Connection (2) I219-V
   Physical Address. . . . . . . . . : 4C-CC-6A-64-E6-FB
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::2cb6:ee01:e72e:ceb1%8(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.2.2(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : maandag 9 januari 2017 23:45:35
   Lease Expires . . . . . . . . . . : dinsdag 10 januari 2017 23:45:36
   Default Gateway . . . . . . . . . : 192.168.2.254
   DHCP Server . . . . . . . . . . . : 192.168.2.254
   DHCPv6 IAID . . . . . . . . . . . : 55364714
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1F-F4-C9-9B-4C-CC-6A-64-E6-FB
   DNS Servers . . . . . . . . . . . : 8.8.8.8
                                       8.8.4.4
   NetBIOS over Tcpip. . . . . . . . : Enabled

Tunnel adapter isatap.home:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . : home
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

That is about all I know for now. Any suggestions would be much appreciated.

Answer 1

I have the same problem myself, but it is not with windows. It is with my ISP.

Try opening Command Prompt and type ping -t 8.8.8.8 (I think you use -t, haven't used Windows in a long time).

Next time it drops look at the output of that command. It should either look like one of these three things:

32 bytes from 8.8.8.8 - this means that the problem is with the server you're connecting to.

Request timed out or Destination host unreachable - now you know that the problem is with your connection, not with the server. Your internet connection or router might be having problems.

Change 8.8.8.8 to your router's IP address, should be 192.168.2.254 or 192.168.2.1.

If that drops like 8.8.8.8, then your internet connection is fine. Either your router or your computer is dropping packets.

If that stays up, bad news - you need a new network card. Your old one is wearing out.

Answer 2

I wonder if the DNS side of things is a red herring (i'm pretty sure it is). I postulate that the issue is a limitation of the router - specifically its ability to do connection tracking.

From the description, I posit that there are too many simulataneous connections, and the router looses track of them - probably preventing new connections before dropping old connections, which would explain why some things continue to work.

This could be caused by a number of things - the most likely is P2P software which makes lots of connections with other systems - likewise it could be malware on one of the devices doing something similar.

At a guess, your PC is running torrenting software (in which case the solution is to reduce the maximum number of simultaneous connections it supports) or it has malware [ in addition to Windows 10 ]

Answer 3

It could be that an excessive number of ports is getting forwarded from the router to the PC. This can happen dynamically via UPnP, so you might try to disable UPnP in the router to check if that solves the issue.

Many "cheap" routers have this issue. Whenever a DNS request is performed, the router expects the answer from the DNS server on a "random" port. Often, these "random" ports are not randomly chosen, but chosen in numerical order. So if one DNS request asks for the answer to arrive on port 2000, the next DNS request will ask for port 2001, the next after that on port 2002 and so on. Now, if you have, for example, the ports 3000-12999 (10.000 ports) forwarded to some machine on the LAN, the DNS answers arriving at these ports will reach the DNS resolver inside the router, but instead go to the machine in the LAN. It will appear that suddenly the DNS servers have all disappeared when the answers from the DNS servers begin to arrive in the forwarded port range. As it takes some time for the response ports to reach this forwarded range, everything will work right after a reset, but then fail at some time.

Surprisingly, this bug is present in many routers. A fix would be that the router's DNS resolver/forwarder should not use forwarded ports to expect answers...but, apparently, this is not getting implemented. Symmetrical NAT would also be an option, but only very few firewalls use Symmetrical NAT.

Anyhow, the issue described above might or might not be the source of the described problem. State table exhaustion (often caused by P2P activities, like when using BitTorrent) has already been mentioned.