PC loses internet connectivity except to Google

I have a Win 7 Pro 64 bit PC on a wired LAN. I regularly access it over Windows Remote Desktop from other Win 7 PC's and a Win 10 PC. The main PC regularly, about 3 times a week, will only connect to Google, (at least to Google Search anyway), or sometimes to no external sources at all. It cannot see my Fritz Box router when this occurs. Other PC's on this network can see out to the internet and connect normally.

I have to do a remote reboot of the main Pc ( shutdown -r ) to get it going again. Can anyone suggest what's happened to it? The only "networky" thing I have done recently is allow network access to the router for my wife's Win 7 Pro 64 bit PC via Wi-Fi. Nothing else is on Wi-Fi. The only thing I have tried is changing DNS servers, which didn't seem to help, although with this fault being intermittent it's hard to say just what might or might not assist.

Did it again last night, tried ipconfig /flushdns It did no good.

Thanks for any help here! Please keep it simple, networking is a black art as far as I am concerned :)

On its face it sounds like a DHCP routing issue in the router with your "main PC." So, I think your problem is in the router and not the PC. If you know how, access the router's GUI Config. and see if you can assign static IP addresses to you PCs. This would also mean for the WiFi side of things as well.

Absent of using static IP addresses, in the "main PC" try an ipconfig /release and ipconfig /renew using an elevated CMD prompt. Your flushdns should also be from an elevated CMD prompt as well. (Right click command and run as Admin)...

Sidenote:

Make sure your router has updated firmware. CVE-2014-9727 : AVM Fritz!Box allows remote attackers to execute arbitrary commands via shell metacharacters in the var:lang parameter t

Instead of hacker plagued RDP, and since this is withen your local network, try TightVNC instead. It may require getting used to and mouse/keyboard response times will be slower, but in my opinion a lot better. If a computer and its monitor are right next to you, try the the free for personal use program InputDirector. I use both of these programs. TightVNC for all the PCs in my house, the VNC Viewer App on my Android phone, and InputDirector to access my laptop sitting next to me on my desk so I can use one keyboard and mouse. Though, I also have VNC setup in the laptop too. I use either or depending on what I need to do on the laptop.

If you want to access your PCs via VNC outside of your local network, then try ZeroTier. This creates a type of VPN connection for which to connect through rather than having to open a port in the router and exposing yourself to the world. If you ever have to open a port in a router then I'd use the hardware based firewall pfSense. ZeroTier also has an Android App...

I've seen many Australian connections have VoIP in their routers. If I had this setup I'd lock it down with pfSense. The fact it seems a lot of your Internet out there seems to be DSL is a bit of a joke to me when everyone here seems to think we have nothing but crap Internet access. Here in the states we have a crap ton of Internet solutions. Cable broadband, fiber, DSL and Sat. Those that don't have great Internet options typically live in the sticks of rural America where your friend is wheat, barley and horses... Nothing wrong with that though. I used to live that life as a child and kinda wish I did today. In the city with your neighbor being so close to you they can hear you sneeze, cough or fart is annoying!


Anyway, look in your router. I strongly feel like the source of your issue is there. You might be able to get a nice ASUS router and flash it with ASUS Merlin or DD-WRT. They both have DSL ability as far as I'm aware.

PS:

Websites like eBay sometimes check your websockets looking for things running on your PC like the aforementioned VNC. They want to know this to help keep security in check because VNC is one such service hackers may use to take over someone's account. If you don't want eBay et al to scan your machine for websockets, and you use the uBlock Origin browser add-on, then add this to the "My filters" list in uBlock Origin:

Code:

# Blocks websockets like eBay local port scan crap.
||ws://
||wss://

To eBay, JP Morgan Chase et al. You need to give the option for the customer to at least use a real base32 2FA (TOTP).