Questions[netplan](server)

The high-level overview is this: I have an Impish Ubuntu server with two interfaces, addresses of 172.16.2.103/24 and 10.1.2.10/24. I would like default traffic to go via the gateway 172.16.2.254. However, when I specify a source address of 10.1.2.10 I want it to have a gateway of 10.1.2.254. What follows works 99% of the time, but I wish for the kernel to select the source IP 172.16.2.103 even when contacting 10.1.2.0/24. This was possible in /etc/networks/interfaces but I haven't been able to figure it out using netplan.

This is what I have in my netplan config:

network:
  ethernets:
    ens160:
      addresses:
      - 172.16.2.103/24
      routes:
      - to: 0.0.0.0/0
        via: 172.16.2.254
      nameservers:
        addresses:
        - 10.1.2.1
        search:
        - localdomain
      optional: yes
    ens192:
      addresses:
      - 10.1.2.10/24
      routing-policy:
      - from: 10.1.2.10
        table: 10
      routes:
      - to: 0.0.0.0/0
        via: 10.1.2.254
        table: 10
      optional: yes
  version: 2

As I say this works fine mostly. I have a routing-policy (aka ip rule) which means that if I change the source address of packets I look up the 10 routing table. However, there is an additional route I wish to remove from main.

This is what I have when I check out the routing tables:

IN1:  me@host:~$ ip route
OUT1: default via 172.16.2.254 dev ens160 proto static
OUT2: 172.16.2.0/24 dev ens160 proto kernel scope link src 172.16.2.103
OUT3: 10.1.2.0/24 dev ens192 proto kernel scope link src 10.1.2.10

IN2:  me@host:~$ ip route list table 10
OUT5: default via 10.1.2.254 dev ens192 proto static

I would like the OUT3 removed, or more accurately moved into the 10 routing table, so that there is no layer2 link to 10.1.2.0/24 in the main routing table. I can do it manually thus:

me@host:~$ sudo ip route del 10.1.2.0/24 dev ens192

But I cannot see how to embed that in netplan. Previously I would have added an up statement to /etc/network/interfaces but that's not an option any more.

Thanks in advance.

This is a fresh install Ubuntu server 20.04.04 system. I'm using networkd and netplan to configure networking. I did not do any custom install steps, just loaded the .iso and installed Ubuntu server through the prompts.

When these machines were shipped from the vendor, Ubuntu was already installed and the network interfaces were named ens1f0 and ens1f1:

root@oldHost2:~# sudo lshw -C network |grep "logical name"
       logical name: ens1f0
       logical name: ens1f1
       logical name: bond0

However after reinstalling the OS (before running netplan) I get....

root@freshHost1:~# sudo lshw -C network |grep "logical name"
       logical name: ens1f0np0
       logical name: ens1f1np1
       logical name: bond0

Across all my sites, we use a netplan config that assumes ens1f0 and ens1f0. I would like all interfaces to match this.

I know you can set the interface name with set-name in netplan (as defined in https://ubuntu.com/server/docs/network-configuration) however you need to already match the interface somehow (using Mac address, etc) which is going to make auto-provisioning a nightmare (if not impossible). A chicken/egg scenario. I have hundreds of machines to provision and I would like to template out my netplan config without knowing the Mac addresses.

I know you can also group together the interfaces in netplan:

  ethernets:
    eports:
      match:
        name: ens*

Which may work for my case, but not all the systems have a simple two NIC setup like this so I'm not sure what the best course of action will be.

My questions to ServerFault...

• Since this logical name is set before Netplan is even ran, what is deciding on this name? How can I override it during OS install/provision?
• What does the np0 and np1 mean in the interface names?

Preface and issue

I have an Ubuntu 21.10 (Impish) server, which network is managed by netplan and systemd-networkd.

My /etc/netplan/01-netcfg.yaml looks like this:

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      addresses:
        - 1.2.3.4/32
        - dead:beef:f00:ba1::2/64
      routes:
        - on-link: true
          to: 0.0.0.0/0
          via: 1.2.1.2
        - on-link: true
          to: default
          via: fe80::1
  vlans:
    eth0.1234:
      id: 1234
      link: eth0
      mtu: 1400
      addresses:
        - 10.0.0.2/25
      routes:
        - on-link: true
          to: 10.0.0.128/24
          via: 10.0.0.1

ip a reports the correct IPs for the three interfaces (lo, eth0, eth0.1234@eth0). Ping and other network traffic works (in-/outbound, outside/vlan).

However, when I reboot the server, sshd.service fails to start at boot time with the following error:

Dec 14 19:18:02 srvnme sshd[1380]: error: Bind to port 22 on dead:beef:f00:ba1::2 failed: Cannot assign requested address.
Dec 14 19:18:02 srvnme sshd[1380]: error: Bind to port 22 on 1.2.3.4 failed: Cannot assign requested address.
Dec 14 19:18:02 srvnme sshd[1380]: fatal: Cannot bind any address.

While boot, the server does not show any issues related to the interface

Dec 14 19:18:02 srvnme kernel: [    1.240607] r8169 0000:22:00.0 eth0: RTL8168h/8111h, de:ad:be:ef:f0:00, XID 541, IRQ 154
Dec 14 19:18:02 srvnme kernel: [    1.240738] r8169 0000:22:00.0 eth0: jumbo features [frames: 9194 bytes, tx checksumming: ko]
Dec 14 19:18:02 srvnme kernel: [    5.046402] r8169 0000:22:00.0 eth0: Link is Down
Dec 14 19:18:03 srvnme kernel: [    8.054249] r8169 0000:22:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
Dec 14 19:18:03 srvnme kernel: [    8.054273] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready

As stated, after a server reboot, I have to hook up a KVM to the server to restart the OpenSSH server to be able to ssh into the server again.

Non-working solutions (so far)

I edited the OpenSSH server configuration (systemctl edit sshd) and tried two approaces:

[Unit]
Requires=systemd-networkd.service
After=systemd-networkd.service
BindsTo=systemd-networkd.service

[Unit]
Wants=network-online.target
After=network-online.target

Both approaches had no effect.

How to fix the OpenSSH does not start at server boot issue?

I'm a newbie to system administration. I've installed remotely a Dell server using iDRAC interface. Server's ip is 200.159.243.146 and everything is fine with it.

Using this interface I've installed Ubuntu Server 20.04 without problem. However, from this system I do not have internet access. This is the result of the command 'ip addr':

This is the content of Netplan configuration file:

As you can see, iDRAC interface has the ip 200.159.243.146 while the ethernet has the ip 200.159.243.147. Outside from this network I can ping the first ip but I can't ping the second one.

Does anybody has a hint of what's going wrong?

I have 2 network interfaces - 1 connected to internal network and 1 connected to external network, both interfaces acquire their IP from DHCP.

By default traffic goes through internal network and external network should be routed separately through a routing table called "public". I'm trying to achieve this using netplan with the following config:

network:
  version: 2
  ethernets:
    ens3:
       dhcp4: yes
       dhcp4-overrides:
         route-metric: 99
    ens4:
       dhcp4: yes
       dhcp4-overrides:
         route-metric: 100
       routing-policy:
         - from: w.x.y.z
           table: 201
         - to: w.x.y.z
           table: 201
       routes:
         - to: 0.0.0.0/0
           via: w.x.v.1
           table: 201
         - to: w.x.v.0/23
           via: w.x.v.1
           table: 201 

After i run netplan apply I'd expect to see the following:

root@my-u18:~# ip route show table 201
default via w.x.v.1 dev ens4
x.y.v.0/23 dev ens4 scope link src w.x.y.z

But in reality the routing table is not populated

root@my-u18:~# ip route show table 201
root@my-u18:~#

However, the routing rules seem to apply:

root@my-u18:~# ip rule
0:      from all lookup local 
0:      from w.x.y.z lookup public 
0:      from all to w.x.y.z lookup public 
32766:  from all lookup main 
32767:  from all lookup default

What am I missing?