No internet access after upgrading to lubuntu 21.04

I have upgraded my lubuntu from 20.10 to 21.04 and then I have no access to internet even though my laptop is connected to wifi. I have tried to set dns in /etc/resolv.conf but to no avail.

Some strange thing I have encountered is that after rebooting if I try to ping 8.8.8.8 it successfully do so but as soon as I try something else like opening firefox and entering a website or trying to apt update the ping process stops and all the packets get failed.

I have tried every similar question on askubuntu but nothing.

Update1: ip route output

default via 192.168.43.1 dev wlp3s0 proto dhcp metric 600
192.168.43.0/24 dev wlp3s0 proto kernel scope link src 192.168.43.199 metric 600

Update 2: ifconfig -a when ping is working:ifconfig ping working

ifconfig -a when ping is not working:ifconfig ping not working

netstat -rnv in both states (they're the same):Netstat

Update 3Device status

Wifi list

3 Answers

I cannot think of a reason why the ping of an address like 8.8.8.8 would be affected by a dns lookup in a browser or apt, they should not affect the routing. Can you post the output of your routes and network adapter configs whilst the ping is working and again when it stops?

ifconfig -a
netstat -rnv

that might shed some light on where the problem is.

Your problem is a little strange ... but anyway do the basics as follows;

-- Check what do you have

sudo nmcli device status

-- Your wifi ap should be visible here

sudo nmcli device wifi list

-- Rescan if your ap doesnt appear

sudo nmcli device wifi rescan 

-- Connect to your wifi

sudo nmcli device wifi connect your_wifi_name password your_password

-- You should see status connected below

sudo nmcli device status

Post the output of the first two commands if you are stuck.
All the best ya.

After upgrading from 20.10 to 21.04 I started getting this error from commands such as ping when trying to resolve hostnames:

Temporary failure in name resolution

However, I could still ping IP address. Strange thing is it was working okay for a little while but after a couple hours the errors showed up. Guess it was due to a timeout.

I tried a bunch of things so I'm not 100% which one fixed it but here are the last things I tried before it started working, I suspect it's one or both.

Check if your resolve.conf file is a real file or symlink:

ls -la /etc/resolv.conf

Mine was a real file so I changed it to a symlink and restarted resolved

sudo rm -rf /etc/resolv.conf
sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
sudo service systemd-resolved restart

If that doesn't fix it try this: