Try to set an address manually in /etc/network/interfaces first:

allow-hotplug eth0
iface eth0 inet static
        address 192.168.0.10
        netmask 255.255.255.0
        gateway 192.168.0.1
        network 192.168.0.0
        broadcast 192.168.0.255

...adapt the numbers for your network. Then try to ping your eero.

If it works, it's a start to exclude some fault reasons and it might be easier
if you can access the WebGUI of your Router again....

Regards, Adrian.

In der Nachricht vom Wednesday, 14 May 2025 07:44:39 CEST schrieb Marc Shapiro
via Dng:
> Yesterday, my internet connection failed. My ISP sent a tech out today.
> He replaced hardware outside, and eventually was able to connect his laptop
> directly to the ethernet where it comes into the house. It did not work
> when connected to my eero router. The tech thinks the current problem is
> with the router. I have my doubts, however, since the desktop computer
> does not get a network connection when plugged into the router or directly
> into the ethernet port.
>
> If I do:
>

>    ifdown eth0
>    ifup eth0

>
> I get the following:
>
> Listening on LPF/eth0/90:2b:34:9d:4d:6b
> Sending on LPF/eth0/90:2b:34:9d:4d:6b
> Sending on Socket/fallback
> DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 6
> .
> .
> 4 more lines like this, each with a different interval
> .
> No DHCPOFFERS received.
> No working leases in persistent database - sleeping.
>
> Did a config somehow get messed up? Is my network card malfunctioning?
> What info do you need to help diagnose this pboblem.
>
> NOTE: Since my desktop has no netork connection, all command results are
> manually typed into this e-mail on my phone.
>
>
> Marc