Static IP doesn't work. So, if the cable it's ok, and I have firmware-realtek installed, where can be my problem?
Can you be more specific? I think it makes sense to really check this manually before getting into automatic configurations..
Can you do the ifconfig && route dance and then post here the output of "ifconfig" (or "ip a") and of "route" (or "ip r").
Then try pinging your gateway and tell/post what happens.
If ping fails or hangs run "dmesg" and look in the last few lines if anything is suspicious.
You may also want to, in a separate terminal, run "journalctl -f" (equivalent of "tail -f /var/log/syslog") and see if it spits anything which may be of relevance.
I've try (just in case) changing the cable and reinstalling the firmware and changing /etc/systemd/network/interfaces to
(snip)
This should go to /etc/systemd/network/eth0.network (you can call it "interfaces" if it makes you happy, but it needs to end with ".network").
Thanks for your help!!!
You're welcome. My eth0.network looks like this
[Match]
Name=eth0
[Link]
MTUBytes=8192
[Network]
DHCP=ipv4
LinkLocalAddressing=no
LLMNR=false
IPForward=true
[DHCP]
SendHostname=true
UseHostname=false
UseDNS=true
UseMTU=false
RouteMetric=10
But many of the options won't be needed (my AR8161 works with the alx module but only if you set the MTU to something bigger than 7*1024), and I set RouteMetric to 10 so that eth0 will be preferred over wlan0, for which I have RouteMetric=20.
Contrary to what I wrote earlier today it actually works reliably. It's not a solid as a failover bond but does the job quite nicely.
Should you decide to test networkd you need to "systemctl enable systemd-networkd" as well as either purge ifupdown or delete any references to your eth0 in /etc/network/interfaces, so avoid conflicts between networkd and ifupdown (as systemd honors -- some -- sysvinit scripts in /etc/init.d, including /etc/init.d/networking.
But first things first. Do it manually and test with ping and/or ssh or something where you can see what's going on.