Cannot reach LAN from Fedora 35 that is sharing Internet

In my cable ethernet configuration, a Fedora 35 workstation has 2 network interfaces:

1. if0 connected to an Internet router via DHCP
2. if1 connected to the LAN with a static IP 192.168.1.x

Machines in the LAN are only connected to this Fedora 35 workstation, and all machines in the network can access Internet.

The problem: my Fedora 35 workstation folio cannot reach machines on the LAN (subnet 192.168.1.0/24). It seems to be a problem with the routing table (some of these entries were mysteriously added after an update):

    Destination     Gateway         Genmask         Indic Metric Ref    Use Iface
    default         _gateway        0.0.0.0         UG    101    0        0 if0
    default         folio           0.0.0.0         UG    20100  0        0 if1
    10.0.0.0        0.0.0.0         255.255.0.0     U     101    0        0 if0
    192.168.1.0     0.0.0.0         255.255.255.0   U     100    0        0 if1
    192.168.1.0     folio           255.255.255.0   UG    100    0        0 if1
    192.168.1.0     folio           255.255.255.0   UG    101    0        0 if0
    folio           0.0.0.0         255.255.255.255 UH    101    0        0 if0

How can I configure the routing table so that traffic to the subnet goes to if1 and all other traffic goes to if0? It seems like this should be simple but I've tried quite a few suggestions and nothing seems to work. If possible, please explain any suggestions in steps, or include a link to reference material, since I don't know much about linux networking.

If there is any way to configure the system to "route the obvious way by netmask", that would really be ideal.

It looks as if your LAN is using the same subnet as that you use to connect to your router. That would be problematic.

Show us

ip a

ip r

so others can comment more meaningfully.

If using NetworkManager...
https://fedoramagazine.org/internet-...etworkmanager/

Thanks for your response, though I managed to get it working. For some reason Fedora doesn't like to share an internet connection on a user-specified IP, so I let it move my LAN over to 10.42.x.x and magically all the weird entries disappeared from the routing table. Everything works fine now. For me it's a bug, but I've filed so many on Fedora this week that I'm just going to ignore this one.

Thanks for your response, though I managed to get it working. For some reason Fedora doesn't like to share an internet connection on a user-specified IP, so I let it move my LAN over to 10.42.x.x and magically all the weird entries disappeared from the routing table.

Again, the issue you had appeared to be due to using the same subnet for the two network interfaces. Shifting the LAN subnet away from 192.168.1.0/24 was required.

GW----<192.168.1.0/24>----Workstation----<10.42.0.0/24>----Local hosts

Not a bug.

No, the Internet is on 10.0.x.x and the LAN moved from 192.168.x.x to 10.42.x.x. It's a bug.

Originally Posted by byron.hawkins No, the Internet is on 10.0.x.x and the LAN moved from 192.168.x.x to 10.42.x.x. It's a bug.

That’s not consistent with the routing table you posted.