Ubuntu home network can't connect to firefox server

Question

My home network has 2 desktops, 1 laptop, 1 printer, and 1 smart TV. All equipment is connected through a modem/router. The desktops are ethernet wired to the router while the laptop, printer and TV are connected by WiFi. Everything worked fine on Ubuntu 16.04LTS until I upgraded one of the desktops (grumpy) from Ubuntu 16.04LTS to Ubuntu 18.04.1LTS.

ping -c3 www.ubuntu.com on grumpy yields "Name or service not known". ping -c3 8.8.8.8 yields 3 packets transmitted, 3 received, 0% packet loss
Mozilla Firefox on grumpy cannot find any server anymore. None of the of the Preferences/General/Network Proxy/Settings options work! Printing from grumpy does not work either! Unexpectedly, Grumpy shows on Settings/Network/Wired/"Connected-1000 Mb/s".

Everything on my home network works - but grumpy (with Ubuntu 18.04.1LTS)! How can I make grumpy work again? Note: I want to keep my existing data. on grumpy intact.

See inside No internet after upgrade from 16.04 to 18.04.

Solution: Start the terminal and type: $ ifconfig

Now you gotta figure out which is your Ethernet interface. Mine is listed as eth0.

Next type: $sudo gedit /etc/network/interfaces

My file only had:

 # interfaces(5) file used by ifup(8) and ifdown(8)

 auto lo

 iface lo inet loopback

Now what you need to do is to add the following lines afterwards:

auto eth0

iface eth0 inet dhcp

Lastly, $ sudo ifup eth0

reboot and you're done. Don't forget to change eth0 with the name of your Ethernet interface.

Original answer shareedit edited Sep 19 at 9:37 Yufenyuy Veyeh Dider 1,3902923 answered Sep 19 at 9:08 Whatnow 211

Answer 1

Ubuntu 18.04 does not work with eth0 or eth1 (example: enp2s0, wlp1s0, etc) and does not work with /etc/network/interfaces (See Yaml)

Create a file:

/etc/netplan/config.yaml

And add your localnet config. Example:

# Let NetworkManager manage all devices on this system (networkd)
network:
  version: 2
# change to "networkd" if you don't want to use NetworkManager
  renderer: NetworkManager
  ethernets:
    enp2s0:
# change dhcp4 to "no" if you want to use static IP. See http://yaml.org/type/bool.html
      dhcp4: yes
      dhcp6: no
      #addresses: [192.168.88.13/24] # uncomment and replace with your static IP/Netmask 
      #gateway4: 192.168.88.1 # uncomment and replace with your gateway
      #nameservers:
      #addresses: [8.8.8.8, 8.8.4.4]  # uncomment and replace with your dns
   enp2s8:
      dhcp4: no
      addresses: [192.168.0.10/24]

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