No Internet connection after disconnecting from VPN in Ubuntu 18.04

It could be related to this bug: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1778946

SOLUTION

Edit the file /etc/ppp/ip-up.d/0000usepeerdns

Replace the following line:

cp -a "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE"

With this code:

cp "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE"
chmod 644 "$REALRESOLVCONF.pppd-backup.$PPP_IFACE"

Restart the network manager:

systemctl restart NetworkManager

I had a similar but different problem. When my Debian 4.19.37-5+deb10u1 loaded, it started NordVPN Version 3.2.0-4 . Whenever I disconnected the VPN, I had no internet connection. Though, local network was still accessible and DNS returned the correct IPs when attempting an internet ping. NordVPN would not reconnect. My only option was to reboot.

None of the solutions presented previously worked for me. Not even restarting manually the network manager service.

I had to uninstall (purge) and reinstall NordVPN following those instructions: https://support.nordvpn.com/Connectivity/Linux/1322207652/Troubleshooting-connectivity-of-Linux-app.htm

Now, I can connect and disconnect NordVPN as much as I want and I have internet access as expected in both situations. Still works after reboot.

Try this, it worked for me.

Disconnect from VPN

sudo rm /etc/resolv.conf
sudo gedit /etc/resolv.conf

add: "nameserver 8.8.8.8" then save

sudo service network-manager reload

OK, so I faced the same problem. My VPN was connected then I pressed CTRL + ALT + F11 then It went into some kind of sleep mode, and then I had to restart my laptop after long pressing power button. So then my internet and Gs connect stopped working, I uninstalled proton vpn but the problem still persisted, So what I did was just reinstalled protonvpn but how? my internet was not working, so I just entered nameserver 8.8.8.8 and nameserver 8.8.4.4 in my /etc/resolv.conf file and then I didn't reload networkmanager and my internet was working but as soon as I reload networkmanager or restart my laptop, resolv.conf changes to its default and internet stopped working. So I just changed resolv.conf file and then installed protonvpn again and tried connecting it, then I got a error message that you need to disconnect other vpn service or buy premium, So that means after uninstalling it, VPN still was in act somewhere so I just closed protonvpn and ran sudo killall vpn and then systemctl restart NetworkManager and viola my internet and Gs connect were working again!!!.

I just wrote the whole scenario above so that someone with this problem doesn't get confused by complex commands answers.

The issues is with how to manage the /etc/resolv.conf. I removed manually the nameserver added by VPN client and restarted the NetworkManager.

/etc/resolv.conf before VPN:

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 14.139.5.5
nameserver 8.8.8.8

/etc/resolv.conf after VPN:

nameserver 10.200.4.1
nameserver 10.200.4.1
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 14.139.5.5
nameserver 8.8.8.8

I removed the top 2 nameserver lines and restarted NetworkManager: systemctl restart NetworkManager.

you need to kill the process, in terminal run the following:

ps -aux | grep vpn

find your process id:

in my case it was 14286

so I ran

sudo kill -9 14286

and, Hola! I can connect to the internet again :)

For Ubuntu 20.04

You can try this

sudo edit /etc/ppp/ip-up.d/0000usepeerdns

Replace

cp -a "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE"

with

cp -a "$REALRESOLVCONF" "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" || {
        rm -f "$REALRESOLVCONF.pppd-backup.$PPP_IFACE" "$REALRESOLVCONF.tmp"
        exit 1
    }

Then restart your network manager

I always had some Internet interruption when using FortiClient VPN. A solution that always works for me :

• Go to your wifi settings
• Click on the settings of your connection
• Click on 'Forget the connection'

Then all I have to do is reconnect to this network (and type the password, hum...) and Internet is back