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Netplan Multiple NICS/VLANS

cn flag
DJFraz

I'm running Ubuntu Server 20.04 and having issues configuring Netplan for 2 nics on 2 different subnets. I'm getting constant random disconnects.

# This is the network config written by 'subiquity'
network:
  version: 2
  renderer: NetworkManager
  ethernets:
    ens18:
      addresses:
      - 192.168.2.233/24
      dhcp4: no
      nameservers:
        addresses:
        - 1.1.1.1
      routes:
        - to: 192.168.2.0/24
          via: 192.168.2.1
          table: 100
      routing-policy:
        - from: 192.168.2.0/24
          table: 100
    ens19:
      addresses:
      - 192.168.1.233/24
      dhcp4: no
      nameservers:
        addresses:
        - 1.1.1.1
      routes:
        - to: 192.168.1.0/24
          via: 192.168.1.1
          table: 101
      routing-policy:
        - from: 192.168.1.0/24
          table: 101

I can reach the server from each network, but I lose connection intermittently. If I back down to one NIC, things stay connected.

The way the network is configured is that network 192.168.1.0/24 can talk to all subnets, but 192.168.2.0/24 can only talk to that subnet alone. The server should "live" on the .2 network and the .1 network will be assigned to certain docker containers.

Thanks for any assistance in advance!

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slangasek

You mention that only the 192.168.2.0 network is reachable via the one interface, while all networks are reachable via the other interface; but you are using routing tables. Routing tables are usually only needed when you have multiple routes for the same target network which you want to use under different conditions. Also, you are declaring that all traffic to the local network should be set via the router on each network. A typical config would instead be:

network:
  version: 2
  renderer: NetworkManager
  ethernets:
    ens18:
      addresses:
      - 192.168.2.233/24
      nameservers:
        addresses:
        - 1.1.1.1
    ens19:
      addresses:
      - 192.168.1.233/24
      nameservers:
        addresses:
        - 1.1.1.1
      routes:
        - to: 0.0.0.0/0
          via: 192.168.1.1
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