Hi. I have a problem. Last night, when I went to bed, the Internet worked fine on my laptop. This morning, not so.

The wifi on my tablet (using now) is fine, and my TV works fine. But on my laptop, which I only use ethernet on, will not work.

Things I remember and have tried:
- Reset router
- Disabled IPv6
- Removed iptables and ufw
- Searched online

Ifconfig showed an ipv6 address before I disabled it, and it looked like half an ipv6 address listed in the inet field.

What I did last night: removed apache. Deleted ntp and ml-sensors from /etc/init.d. (A few other startups like hardware temperature sensors, etc. Nothing serious or network related.)

Could someone help me with this please?

ntp nothing serious? well i guess it's all relative.
there's quite a lot you're not telling us:
- why and how disable ipv6?
- you cannot remove iptables, it's part of the kernel, afaiu. anyhow, show us exactly what you did there.
- searched - and found - what?
- why did you have apache installed in the first place, and what exactly did you uninstall?
- which debian version?

just for starters, show usand how are you connecting to the network.

edit:
in the end, you just need to undo what you did.
i hope you took some notes.
and in the future, do backups before things go pear-shaped.

ntp is not mandatory.

Apt remove ufw also removed ip tables.

Searched for solutions.

It's not relevant why I had apache installed.

Stretch

I can't ping Google's DNS servers.

Thanks for your help.

Well, after hours of testing this is what I've got.

There's no routing table information. (route - n)

With 8.8.8.8 in resolve.conf or without, ping www.google.com reports connect: no network connection. The nameserver gets changed to ipv6 after I change it to 8.8.8.8, even if I disable ipv6 in sysctl.conf.

I've tried changing the interfaces to managed in Network Manager.conf... that did nothing.

I've tried listing the interfaces in /etc/network/interfaces, that changed nothing.

I turned off dhcp in the router, and that changed nothing too.

I tried connecting to my tablet hot-spot, and I still couldn't get through to the Internet.

There are no firewall rules stopping anything, including port 53.

Tech support factory reset the router for me. Still can't get through.

The strange thing is, my TV uses the same Internet, and it's been working fine all day.

Can someone with more experience please help with this problem? Many thanks.

Update.

I just had a good idea and booted up my Huawei mini router. My laptop connected without a hitch.

So, even though my tablet connects to my primary router, something in the router or service is blocking my laptop via WiFi and Ethernet.

The tech guys will have to figure it out when they come here tomorrow.

Closed.

At a minimum, examining the IP address assigned and default route is a good place to start. These commands can provide that information:
If the above check out, you can try pinging other hosts on the LAN, and then pinging a well-known internet address as part of the initial diagnostics.

If it's just name resolution not working, check for a valid nameserver...
This basic info can help others to assist further. (Better than blindly turning things off or disabling them without a clear understanding of what's actually wrong.)

Thank you.

You have to remove your old connection. I mean, you need to remove your laptop IP address from your router received IP, and to start a new connection. It worked for me very well

Have you tested the ethernet cable or tried using a different, known-good one?