How would you resolve this issue: Your server's internet randomly becomes inaccessible until reboot. (Ubuntu 22.04, Netplan)
I've been having this issue very sporadically (sometimes a couple times a week, sometimes once a month). I'm curious as to how the more veteran folk here would try and narrow down the cause of this issue.
Are you able to access the server's Linux shell via KVM or out-of-band management during the Internet outage? If so, I would first check the kernel log for any errors. I'd then follow up with a PING to the local gateway within the same IP subnet to validate Ethernet connectivity. After that I'd start performing PINGs and traceroutes to subnets beyond the local gateway to see what's going on with tcpdump capturing all interface traffic in the background.
The tracert equivalent that I use would be traceroute or mtr. If you can get a response from the gateway and access the server locally, it would indicate an IP routing issue as local subnet traffic is working.
Instead of pinging a domain name, what happens if you ping a public IP like Google DNS (8.8.8.8)? The error you're seeing could be related to a DNS resolution issue although that should not affect access to your server.