Internet connection lost and recovered by turning the machine off and on.
 

Acer Aspire One Cloudbook 14 (A01-431-C8G8)
Linux kernel 4.19
Debian 10
Firefox Quantum 68.7.0esr (64-bit)

Hi: today I lost connection (wi-fi) with Internet. The NetworkManager icon said "Wi-Fi network connection active" but 'ping 8.8.8.8' (google) gave "Network unreachable". So I was left without Internet for most of the day.

Now it occurred to me to turn the machine off and on. And this time I could connect to Internet. So the problem was neither the wi-fi modem nor the ISP. What could have happened?

I don't know what could have happened, but, if it happens again, try disconnecting, then reconnecting, without turning the machine off. This happens to me from time to time and disconnecting/reconnecting usually fixes it.

In my case, I think it's happening because the computer is getting a bit long in the tooth.

Thanks, I'll do that. But what is the tooth?

Could also be the router.

I once complained to my isp about drop-outs and the suggestion was "try shutting down and re-starting your router". It worked, but it did sound like the call-centre man was trained by Microsoft!

But if the problem was solved by turning the machine off and on, that means that everything outside the computer was working fine! The only thing to blame, by exclusion, has to be the computer itself. Don't you agree?

If you turned the router off and on and that solved the problem, it does not mean that the router or the ISP was to blame.

I got shared Internet on an Ethernet cable from the landlord who mostly supplies the neighbourhood with WiFi access. He sometimes changes equipment, implements new software, and doesn't explain much if strange things are happening. I got my own switch and my own router for WiFi. I got a laptop, a PC and a single-board computer.

About a month ago, my PC lost suddenly Internet connection. I didn't get no more DNS service. The next day, it worked fine but a few days later that happened to the laptop. Fortunately, the laptop got both, WiFi and Ethernet cable. And the WiFi router never failed. My single-board computer running Ubuntu also got an IP address every time.

Within more than three years, that never ever happened before. The landlord suggested only to use static addresses and this helps. Using nmap, I can see that the LAN is not overcrowded. There are generally only twenty hosts connected. So, I can't see a reason why DHCP seems to fail from time to time.

I do not agree with that logic.

For What?

It could be that there's just some problem at the isp and disconnecting and then re-applying for a connection works. No-one wanted to explain the solution to me.