0

I've followed the highest voted answer by heynnema on this Linux Ubuntu Server 20.04 LTS: 'Network Unreachable' question on netplan:

  1. Changed /etc/netplan/'01-network-manager-all.yml content to
  network:
      version: 2
      renderer: networkd
      ethernets:
        enp4s0:
          addresses:
            - 192.168.1.200/24
          gateway4: 192.168.1.254
          nameservers:
            addresses:
              - 8.8.8.8
              - 8.8.4.4
  1. ran following commands
sudo netplan generate

sudo netplan apply


reboot # mandatory

and am now cut off from the internet on that machine. I had made a copy of the original '01-network-manager-all.yml' file and ran the commands specified in the answer again on that,

sudo netplan generate

sudo netplan apply


reboot # mandatory

but to no success. How can I undo those netplan changes?

Edit:

ip a output:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: wlp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 5c:ba:ef:cd:c6:19 brd ff:ff:ff:ff:ff:ff
    inet 192.168.30.19/24 brd 192.168.30.255 scope global dynamic noprefixroute wlp1s0
       valid_lft 604268sec preferred_lft 604268sec
    inet6 fe80::44ae:37a2:66c5:b8ce/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: lxcbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 00:16:3e:00:00:00 brd ff:ff:ff:ff:ff:ff
    inet 10.0.3.1/24 brd 10.0.3.255 scope global lxcbr0
       valid_lft forever preferred_lft forever
4: br-bd526d132fb7: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default 
    link/ether 02:42:24:07:b4:a3 brd ff:ff:ff:ff:ff:ff
    inet 172.18.0.1/16 brd 172.18.255.255 scope global br-bd526d132fb7
       valid_lft forever preferred_lft forever
    inet6 fe80::42:24ff:fe07:b4a3/64 scope link 
       valid_lft forever preferred_lft forever
5: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:fd:ac:22:cc brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
7: vethc2e94a7@if6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br-bd526d132fb7 state UP group default 
    link/ether 1e:00:18:36:2a:c7 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet6 fe80::1c00:18ff:fe36:2ac7/64 scope link 
       valid_lft forever preferred_lft forever
user_90809
  • 1
  • Is this Ubuntu Desktop or Server installation? Is that your correct gateway address? – mpboden May 07 '23 at 19:13
  • Ubuntu Desktop Installation and the gateway address was wrong as I just found out, but changing it, executing the commands and rebooting did not fix the problem. – user_90809 May 07 '23 at 19:38
  • If it’s a Desktop installation, change the renderer line to renderer: NetworkManager. The desktop install doesn’t use networkd – mpboden May 07 '23 at 19:49
  • Done. The issue unfortunately is still there. – user_90809 May 07 '23 at 19:57
  • I just don't know why reverting to the original file content does not fix the network connection. – user_90809 May 07 '23 at 19:59
  • The Desktop installation uses whichever backend you configure it to use. – slangasek May 07 '23 at 21:28
  • Why are you using static networking instead of DHCP? – slangasek May 07 '23 at 21:29
  • Please update your question to include the output if ip a. – mpboden May 07 '23 at 22:03
  • @slangasek True…Desktop can use networkd. I misspoke. But by default, Desktop is using Network Manager. So if OP wants to use networkd, then they’d have to stop, disable, and mask Network Manager service. Then unmask, enable, and start systemd-networkd service. I made an assumption that this hasn’t been done. – mpboden May 07 '23 at 22:16
  • You can choose whichever (networkd vs. NetworkManager) you prefer, but we strongly recommend NetworkManager for desktop users unfamiliar with the details of networking. netplan will set up your network exactly the way you specify, even if your specification is wrong. – user535733 May 08 '23 at 00:42
  • @user535733 And how do I revert to NetworkManager? My 01-network-manager-all.yaml file in /etc/netplan/ contains the original file content and I tried to do exactly that. – user_90809 May 08 '23 at 07:32
  • @mpboden I want to revert back to the original NetworkManager solution. I don't want to use networkd. Will update my question with ip a output. – user_90809 May 08 '23 at 07:37
  • Your new YAML file is setting up a static IP on the enp4s0 interface, but the output of ip a indicates that you don’t have an interface of that ID. So I would start by deleting the YAML file you created and restore the original so that there is only one YAML file in the /etc/Netplan directory. – mpboden May 08 '23 at 16:53
  • @mpboden That's what I did when I noticed the internet connection was gone, which didn't help. – user_90809 May 09 '23 at 07:36

0 Answers0