New to Ubuntu - Ethernet won't come up

[Robert Moskowitz]

One issue might be that I know the Zotac has a gigabit adapter and it is 
plugged into a 100Mb switch.

How can I determine that the adapter detects this interface speed?

On 5/13/25 4:19 PM, Robert Moskowitz wrote:
> I am new to Ubuntu.  Decades with Fedora and CentOS.  Only now needing 
> to work with Ubuntu.
>
> I am building a server to run Mail-in-a-Box which uses Ubuntu 22.04
>
> https://mailinabox.email/
>
> I have a Zotac Zboxnano that was sitting around with an old Centos7 
> build.  I pulled the drive, put in an SSD card I had sitting around 
> (had Fedora 24 on and not needed), downloaded the Ubuntu 22 ISO and 
> successfully did the install.
>
> I had no problem, that I saw, in accessing the Internet via the DHCP 
> server on my AT&T router for the install.  I did not select to add any 
> apps, because I don't know what I might want and Mail-in-a-Box setup 
> says it will install everything needed.
>
> So I reboot (pulled the USB DVD player) and watched the boot up.
>
> The booting seemed to have a problem with network services?  Time out 
> after something over 2min.
>
> I logged in as me, and no network.  Using SUDO, I set root's password 
> and su.
>
> I played around with "ip addr add" and such and tried to bring up the 
> interface but it stayed down.
>
> I tried editing the yaml and use netplan without success.
>
> I shot the day, sad to say.
>
> Nothing in journalctl.  No indication anything has happened.  The 
> lights are on the ethernet port, indicating data in and out?
>
> But can't get the interface up.  It obviously was for the install and 
> it worked fine with C7.
>
> the netplan file has a dhcp4: true line; no dhcp6: line.  I know I 
> have dhcp4 on that subnet.  Also public addr and I tried to hand 
> config one of those.
>
> Can I please have some pointers to try and figure this out?
>
> thanks
>
>
>