Fedora 33 with two NICs for two Sub-C nets

[benpack]

@vgaetera

nmcli connection show

nmcli connection show
NAME UUID TYPE DEVICE
DSL 93d1473b-05c2-40da-b29a-38ef93e78ea1 ethernet enp13s0
Kabelgebundene Verbindung 1 24aa5b4b-e18b-45dd-9354-91a17fe752e3 ethernet enp0s20f0u5u1u2
LAN 0e201820-dab0-49d7-a0f4-6cd039e2d81d ethernet enp0s31f6
virbr0 35dfe4c9-abfb-4206-ac4e-c1ab7dd47b76 bridge virbr0
enp0s20f0u6u1u4 77f6538b-d57e-3936-ac95-622a5a72816e ethernet –
enp14s0 c229b834-3eee-3bce-8977-fd92a729c25a ethernet –
Galep5 fdcf689d-8ae8-3c76-b741-660344b456d7 ethernet –
GALEP5 a81ec101-86f8-3580-80e7-a611eae8623d ethernet –
USB-GigE Adapter c8fd5e3c-6bef-3109-9cf8-4b1e5249a829 ethernet –

[benpack]

@vgaetera

nmcli connection modify id LAN ipv4.never-default yes ipv6.never-default yes
nmcli connection up id LAN

It works now Thanks !

If it is not too much work:
What is actually changed by the the command(s) ?

And will it be persistent?

[vgaetera (Vladislav Grigoryev)]

@benpack

What is actually changed by the the command(s) ?

The internet should be routed via the DSL connection.
The LAN connection should be used to access hosts in the LAN network.
This resolves the routing collision with the duplicate default gateway.

@benpack

And will it be persistent?

Yes.

[gus67 (Gunther S.)]

@benpack

What is actually changed by the the command(s) ?

Actually NM is told to NOT set a default gateway for the LAN connection. But since the connection is static, meaning you set it up manually, you should not have set a gateway for LAN in the first place

Also you should consider to ad host information for all hosts in your local network to the DNS-server at 192.168.178.5 to get your local dns-resolution working.

[benpack]

And this was different in versions before F33 since it wasn’t a problem then?

[vgaetera (Vladislav Grigoryev)]

@benpack

enp0s31f6 and enp13s0 have static IP adresses

Then you can simplify the config:

nmcli connection modify id LAN \
ipv4.gateway "" ipv4.never-default "" \
ipv6.gateway "" ipv6.never-default ""
nmcli connection up id LAN

@benpack

And this was different in versions before F33 since it wasn’t a problem then?

Downstream interfaces should not configure the default gateway anyway.

[gus67 (Gunther S.)]

@benpack

And this was different in versions before F33 since it wasn’t a problem then?

Well, actually it shouldn’t be a problem now as well since the LAN route should simply be discarded due to not having a connection to the internet and the route with the next higher metric should be testen and used on success. Maybe route-validation changed either in NM or the kernel? I really don’t know for sure.

But having the configuration right in the first place always makes it easier

EDIT:
Think of the gateway setting as ‘use address xxx.xxx.xxx.xxx to reach network yyy.yyy.yyy’. If you have a direct connection, a gateway is not needed.

[huben (Ben)]

Edit
Has been already said.