[SOLVED] No LAN Connections After Ubuntu Server 18.04 Install

[mhumm2]

Now that I have a little more discretionary time, I decided to get my homebuilt NAS up and running. To that end I did the following:

- burned the iso to a DVD on my AMD-64 computer
- Installed from the DVD to a Samsung 64GB Flash drive using my AMD-64 computer (Bionic had no issues using the LAN connection to DL SW and updates).
- Performed the reboot and removed the DVD as directed. The system rebooted from the flash drive without issue.
- I shutdown the system
- I removed the flash drive
- I installed the bootable flash drive into the server (Supermicro X9SCL-F // Intel G2030 @ 3.0GHz, dual core)
- The system booted without issues and I logged in.
- I attempted to perform a sources update (sudo apt-get update). I entered my PW and the update errored out.
- I ran ifconfig and discovered the only LAN interface I have is L0.

The NAS does have an IPMI input. To make sure, I connected all 3 RJ-45 ports to the modem; lights come on and blink as usual, but I still only get the L0 interface.

Is the problem the fact that it installed on one computer and running on another? Please advise.

[oshunluvr]

Time to learn something new! 18.04 uses netplan to configure network connections. Since you didn't give any info about your NICs or current setup, how are we supposed to help?

[oshunluvr]

BTW, I have no idea what an "IMPI input" is or how it applies to network issues.

[Snowhog]

Intelligent Platform Management Interface: https://en.wikipedia.org/wiki/Intell...ment_Interface

[mhumm2]

I'm sorry for the confusion and typing dyslexia. Since posting, I did find out some things about Netplan. The problem now is, My netplan configuration isn't working. In fact, I've tried 2 different configs copied right off the internet and neither one could be applied.

From ifconfig, I discovered one of my NAS NICs is eno1.

Here's the simple one.

network:
    ethernet:
         eno1:
              addresses: [ ]
              dhcp4: true
              optional: true
version: 2

sudo netplan apply errored out on me.

Invalid YAML at //etc/netplan/01-cfg.yaml line 1 column 0: found character that cannot start any token.

I created the file with nano. Even when I cat the file, I only see the first word on line 1, "network:." The first character is "n." Of course wouldn't that be line 1 character 1?

[GreyGeek]

....

Invalid YAML at //etc/netplan/01-cfg.yaml line 1 column 0: found character that cannot start any token.

....

This is a yaml based configuration system, which should simplify the process.

Wasn't the Paper Work Reduction Act supposed to reduce gov paper work?

I would assume that netplan is integrated with systemd and one would use "sudo systemclt restart netplan", or something like that, to start the service. Just using "sudo netplan apply" is so anti-systemd.
It turns out that netplan hands off control to networkd, which is part of the SystemD.
Here is a helpful post with lots of useful CLI commands:
https://www.claudiokuenzler.com/blog...etplan-systemd


Now I'll need to study netplan to figure out how to integrate my IPv6 tunnel with it. With the current system it is drop dead easy. All I needed to do was add

auto he-ipv6
iface he-ipv6 inet6 v4tunnel
        address 2001:470:abcd:abc::2
        netmask 64
        endpoint ww.xx.yy.zz
#        local w.x.y.z
        local 192.168.11.100
        ttl 255
        gateway 2001:470:abcd:abc::1
        dns-nameservers 2606:4700:4700::1111
        dns-nameservers 2606:4700:4700::1001

to /etc/network/interfaces

EDIT:
After a little searching I found a possible way to add my IPv6 tunnel:
https://askubuntu.com/questions/1051...ces-to-netplan

I also found this caveat:

http://jrs-s.net/2018/06/17/sample-n...-ubuntu-18-04/

HUGE LIFE PRO TIP: against all expectations of decency, netplan refuses to function if you don’t indent everything exactly the way it likes it and returns incomprehensible wharrgarbl errors like “mapping values are not allowed in this context, line 17, column 15” if you, for example, have a single extra space somewhere in the config.

NetworkManager can be set to be the "renderer" in the yaml file and that allows NetworkManager's GUI to be used. At first I was skeptical about netplan, but after further investigation it is just another tool. If networkd is used as the renderer then the CLI is your tool.

EDIT-EDIT:
It turns out that I may be able to create /etc/network/interfaces and add my tunnel script to it, then save the interfaces file, and reboot, or restart networking using the commands shown below

ip flush he-ipv6

then restart networking service

systemctl restart netwroking.service

The full documentation for netplan is here:
https://github.com/CanonicalLtd/netp...doc/netplan.md

[mhumm2]

Interesting GG. I checked my interfaces file and found a note about how to initialize netplan by installing "ifupdown." Of course I can't install it because I don't have internet access. Only LO for loopback.

[GreyGeek]

Interesting GG. I checked my interfaces file and found a note about how to initialize netplan by installing "ifupdown." Of course I can't install it because I don't have internet access. Only LO for loopback.

Don't waste time trying to install ifupdown. With 18.04 and onward that's old school.

From what I've read, if you have NetworkManager installed, and you edit /etc/netplan/01-network-manager-all.yaml
and make it look like this:

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: [B]NetworkManager[/B]

and run
sudo netplan apply
your NetworkManager GUI should allow you to see your wifi router and connect. (Or you ETH0 cable if you use it).

/etc/netplan/01-network-manager-all.yaml is used as the config file because it refers to the desktop or workstation, but filenames are not specific because netplan looks in /etc/netplan/*.yaml for any file with a .yaml extension. The name is for your benefit. You could call it x.yaml.

If you don't have NetworkManager installed then you'll have to go the CLI route using netplan itself, and using networkd as the renderer.

[mhumm2]

running lshw -c net is what told me that my two NICs (eno1 and enp2s0) are disabled. I entered:

sudo ip link set eno1 down
sudo ip link set eno1 up

I did the same for enp2s0 and now they both are listed as "*-Network" instead of "*-DISABLED." So then I tried to run an update and I still do not have inet access.

I'll try deleting the interfaces file I created and I'll change my yaml file to the 3 lines you suggested GG.

[mhumm2]

Okay, I deleted the interface file text I added so the only part that remains is the original remmed-out text. Then rewrote the 01-netcfg.yaml file with the 3 lined one you suggested GG and it worked! At least it didn't abort when I "tried" it so I applied it and it took. Then I tried to update my sources and again no joy! I still get either "unable to resolve..." or "Failed to fetch..." Now what?

[mhumm2]

FIXED IT!!! I had to add the lines for both nics for dhcp4: yes and now they're seen and usable. I was even able to update my sources! Thank you GG, et al, so much. It turns out I also had a tab-key entry that was causing problems... spaces only. Okay. TTYL.

[GreyGeek]

Let's see if you have any address assignments. What does
ip a
show?

[mhumm2]

it displays:

eno1
inet 192.168.1.76/24
brd 192.168.1.255 scope global dynamic eno1

enp2s0
inet 192.168.1.94/24
brd 192.168.1.255 scope global dynamic enp2s0

I'll set them up as static at some point.

[oshunluvr]

FYI, static looks like:

[FONT=monospace][COLOR=#000000]network:[/COLOR]
  version: 2
  renderer: networkd
  ethernets:
    eno1:
      dhcp4: no
      dhcp6: no
      addresses: [192.168.1.250/24]
      gateway4: 192.168.1.1
      nameservers:
        addresses: [8.8.8.8,8.8.4.4]

[/FONT]

Obviously, use your desired IP address and nameserver addresses