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lion
Asked: 2022-01-12 21:18:36 +0800 CST

Networking: 4 Separate Subnets Default Route Consistency Warning?

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Just installed Ubuntu and one of my network card ports does not work and has no ping to it's IP - eno2.

Netplan as configured during install:

    # This is the network config written by 'subiquity'
network:
  ethernets:
    eno1:
      addresses:
      - 11.22.33.210/24
      - 1a2a:3a4a:5a6a:16::601/64
      gateway4: 11.22.33.1
      gateway6: 1a2a:3a4a:5a6a:16::1
      nameservers:
        addresses:
        - 1.1.1.1
        - 1.0.0.1
        - 8.8.8.8
        - 8.8.4.4
        - 2606:4700:4700::1111
        - 2606:4700:4700::1001
        - 2001:4860:4860::8888
        - 2001:4860:4860::8844
      accept-ra: no
    eno2:
      addresses:
      - 22.33.44.210/24
      - 1a2a:3a4a:5a6a:17::602/64
      gateway4: 22.33.44.1
      gateway6: 1a2a:3a4a:5a6a:17::1
      nameservers:
        addresses:
        - 1.1.1.1
        - 1.0.0.1
        - 8.8.8.8
        - 8.8.4.4
        - 2606:4700:4700::1111
        - 2606:4700:4700::1001
        - 2001:4860:4860::8888
        - 2001:4860:4860::8844
      accept-ra: no
    eno3:
  addresses:
  - 33.44.55.210/24
  - 1a2a:3a4a:5a6a:18::603/64
  gateway4: 33.44.55.1
  gateway6: 1a2a:3a4a:5a6a:18::1
  nameservers:
    addresses:
    - 1.1.1.1
    - 1.0.0.1
    - 8.8.8.8
    - 8.8.4.4
    - 2606:4700:4700::1111
    - 2606:4700:4700::1001
    - 2001:4860:4860::8888
    - 2001:4860:4860::8844
    - 2606:4700:4700::1111
    - 2606:4700:4700::1001
    - 2001:4860:4860::8888
    - 2001:4860:4860::8844
  accept-ra: no
eno4:
  addresses:
  - 44.55.66.210/24
  - 1a2a:3a4a:5a6a:19::604/64
  gateway4: 44.55.66.1
  gateway6: 1a2a:3a4a:5a6a:19::1
  nameservers:
    addresses:
    - 1.1.1.1
    - 1.0.0.1
    - 8.8.8.8
    - 8.8.4.4
    - 2606:4700:4700::1111
    - 2606:4700:4700::1001
    - 2001:4860:4860::8888
    - 2001:4860:4860::8844
  accept-ra: no
  version: 2

Ran this

echo 101 eno1-route >>/etc/iproute2/rt_tables
echo 102 eno2-route >>/etc/iproute2/rt_tables
echo 103 eno3-route >>/etc/iproute2/rt_tables
echo 104 eno4-route >>/etc/iproute2/rt_tables

rc.local

#!/bin/bash 

# Increasing The Transmit Queue Length
/sbin/ifconfig eno1 txqueuelen 10000
/sbin/ifconfig eno2 txqueuelen 10000
/sbin/ifconfig eno3 txqueuelen 10000
/sbin/ifconfig eno4 txqueuelen 10000
/sbin/ifconfig lo txqueuelen 10000
#routes
ip route add default via 11.22.33.1 dev eno1 table eno1-route
ip rule add from 11.22.33.210 lookup eno1-route
ip route add default via 22.33.44.1 dev eno2 table eno2-route
ip rule add from 22.33.44.210 lookup eno2-route
ip route add default via 33.44.55.1 dev eno3 table eno3-route
ip rule add from 33.44.55.210 lookup eno3-route
ip route add default via 44.55.66.1 dev eno4 table eno4-route
ip rule add from 44.55.66.77 lookup eno4-route

Getting this error when applying netplan.

** (generate:5742): WARNING **: 05:13:22.079: Problem encountered while validating default route consistency.Please set up multiple routing tables and use `routing-policy` instead.
Error: Conflicting default route declarations for IPv4 (table: main, metric: default), first declared in eno2 but also in eno4

All IPs both IPv4 and IPv6 seem pinglable after reboot. What is going on? I already have different routing tables. Conflicting default route declarations!?

ip route list returns

default via 22.33.44.1 dev eno2 proto static 
default via 33.44.55.1 dev eno3 proto static 
default via 11.22.33.1 dev eno1 proto static 
default via 44.55.66.1 dev eno4 proto static 
44.55.66.0/24 dev eno4 proto kernel scope link src 44.55.66.210 
11.22.33.0/24 dev eno1 proto kernel scope link src 11.22.33.210 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 
22.33.44.0/24 dev eno2 proto kernel scope link src 22.33.44.210 
33.44.55.0/24 dev eno3 proto kernel scope link src 33.44.55.210
networking

2 Answers

  1. You have different routing tables, but when you use the gateway4 and gateway6 shorthand, this does not make use of those routing tables. To get the results you want, you will need to spell out the default routes as routes: instead as described at https://netplan.io/reference/#default-routes.

    • 1

  2. "Getting this error when applying netplan.

    ** (generate:5742): WARNING **: 05:13:22.079: Problem encountered while validating default route consistency.Please set up multiple routing tables and use routing-policy instead. Error: Conflicting default route declarations for IPv4 (table: main, metric: default), first declared in eno2 but also in eno4"

    Check the /etc/netplan folder for more than one YAML configuration file.

    If more than one file, clean out for a single file may cure the conflict.

    I was having this error message, and discovered a 99- netplan file was conflicting with the standard 00-installer-config.yaml file.

    Deleting the 99 file cured the problem.

    • 0