Post the output of the ip a command for eth0 and enp2s0 adapters.

Did you try the ping command?

Wired not enabled or cable connected presently.

tom@tom-iMac:~$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether 40:6c:8f:0a:fa:20 brd ff:ff:ff:ff:ff:ff
3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 7c:c3:a1:aa:35:23 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.106/24 brd 192.168.1.255 scope global dynamic noprefixroute wlp3s0
valid_lft 77230sec preferred_lft 77230sec
inet6 fe80::68d8:2077:edf1:8dd8/64 scope link noprefixroute
valid_lft forever preferred_lft forever

tom@tom-Inspiron-1521:~$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:19:b9:7e:49:f9 brd ff:ff:ff:ff:ff:ff
inet6 fe80::ae31:b46:3a31:3328/64 scope link noprefixroute
valid_lft forever preferred_lft forever
4: wlx74da386f57f5: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether 74:da:38:6f:57:

1) Go to "Edit Connections". I don't know precisely how this will show up on your computers. Maybe you right click on the networking icon in the taskbar.

2) Double click on the wired connection (it might be something like "Wired connection 1" or "enp0s25")

3) Click on IPv4 Settings

4a) If this is your DHCP client computer (the one with WiFi disabled), select "Automatic (DHCP)" for Method
4b) If this is your DHCP server computer (the one with WiFi enabled), select "Shared to other computers" for Method

After completing steps 1-4 on both computers, connect the cable between them.

Under no circumstances will the connection work with only two DHCP clients and zero DHCP servers.

On my computer, the list of options for Method is:

Automatic (DHCP)
Automatic (DHCP) addresses only
Manual
Link-Local Only
Shared to other computers
Disabled

Not much point of us trying to help if the cable is not connected. When you are ready let us know. If you added an IP address via IP command it should remain assigned until you reboot or delete it.

iMac - Wireless enabled - IPv4 set to Automatc (DHCP)
om@tom-iMac:~$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 40:6c:8f:0a:fa:20 brd ff:ff:ff:ff:ff:ff
inet6 fe80::4f7d:624b:d707:2a0a/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 7c:c3:a1:aa:35:23 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.106/24 brd 192.168.1.255 scope global dynamic noprefixroute wlp3s0
valid_lft 74730sec preferred_lft 74730sec
inet6 fe80::68d8:2077:edf1:8dd8/64 scope link noprefixroute
valid_lft forever preferred_lft forever


Dell wifi disabled Wired IPv4 set to link-local only

tom@tom-Inspiron-1521:~$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
link/ether 00:19:b9:7e:49:f9 brd ff:ff:ff:ff:ff:ff
3: wlx74da386f57f5: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether 74:da:38:6f:57:f5 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.113/24 brd 192.168.1.255 scope global dynamic noprefixroute wlx74da386f57f5
valid_lft 77173sec preferred_lft 77173sec
inet6 fe80::7933:8cea:1751:7deb/64 scope link noprefixroute
valid_lft forever preferred_lft forever

Which method do you want to use?

Set each interface address using network manager manual configuration.
Set each interface address manually via ip command.
Use share to other computers.

I assume the cable is connected. I assume you just want to copy / share files between computers?

I clicked on the Network manager icon

Set each interface address manually via ip command.
Use share to other computers. [/QUOTE]

Yes I did that earlier. Both were set to Automatic at the time. Thought it would go away after the cable was unplugged.

I assume the cable is connected. I assume you just want to copy / share files between computers?[/QUOTE]

Cable is still plugged in. Yes want to share a large volume of files. Also just want to know how to do it.

Maybe I need to to start over again - Tablula rasa.

FYI I got my Comptia certification years ago but bombed on networking. My nephew started programming when he was in elementary school in 1968. He adapted to Linux close to the beginning. Says that Networking his hard for him. To me networking seems like the thighbone is connected to the shoulder bone.

FWIW, I've used the Network Manager GUI method for years and years, just because it was the simplest thing and it worked without giving me much grief. My main use case is actually sharing the WiFi network connection of a laptop to a desktop computer. That way, the desktop computer doesn't need any WiFi hardware.

The fact that it's possible to do fast file transfers between them is just a bonus that I occasionally use here and there.

However, I have never seen "Shared to other computers" as unavailable or grayed out. There might be a missing dependency that Debian installs by default along with Network Manager or something.

If you choose manual configuration from Network Manager, in the IPV4 configuration tab set the IP address as 10.0.0.1, netmask as 255.255.255.0 on one computer and 10.0.0.2 255.255.255.0 on the other. Gateway and DNS addresses not required. If that works you should be able to ping from one computer to the other.

I am running Linuxmint 21,2 Cinnamon to the latest update. I do not see "Shared to other computers" at all anywhere. Not even greyed out. I have clicked on the Network Manager and all of it's settings pages to no avail. I do see Automatic (DHCP), Manual, and Link-Local options on the IPv4 section. On the Dell laptop it is set to Link-Local. Does Link-Local mean "Shared to other computers"?

Network Manager (network@cinnamon.org) Network manager applet.

Both the iMac and the Dell Laptop have wifi hardware. The Dell is using a usb wifi dongle.

No, Link-Local is something else. I've never used it, but it might work if you set both wired connections to "Link-Local".

I don't know how it works at all, but I think that the computer with WiFi disabled will, at that point, ONLY be able to communicate with the other computer.

Linked-Local on both did the trick.

1 members found this post helpful.

Looking around LinuxMint discussion forums, the "Shared to other computers" option seems to exist on them. These are the options that should appear in the IPv4 Settings tab:

Automatic (DHCP)
Automatic (DHCP) addresses only
Manual
Link-Local Only
Shared to other computers
Disabled

All of these options are different from each other. The options in IPv6 Settings tab are a bit different, but you can try using IPv6 instead of IPv4. I'm personally not familiar with IPv6.

Good. link-Local is an automatic ip address configuration for when a DHCP server is not available. Ipv4 addresses are in the range of 169.254.0.0/16. It really only used for standalone LANs since traffic is not forwarded.

I am not seeing it in Linuxmint 21.2 Cinnamon IPv4 page. Maybe those are old discussions. What Linuxmint forums did you see it on? https://forums.linuxmint.com or something else?