Why is the server only pingable and sshable in rescue mode?

Question

linux

Hello, such a problem. There is a server (hardware) on CentOS7, connected via twisted pair to the network, it has several virtual machines (KVM). There was such a problem: the server simply ceases to be available, from the word completely i.e. I try to ping the server IP - I get "Host Unreachable", similar when trying to connect via SSH. At the same time, iptalbes / firewalld are disabled from the server side, there is a network (outside too). What is interesting - virtual machines that calmly ping on it and can connect to them.
At the same time, if you reboot into rescue mode, it becomes available via SSH and pings.
Network interfaces (one not connected) in the bridge and it is listed as a network device for virtual machines.

Answer 1

"Host Unreachable" - this looks like a problem "on the way" to the server.
Or in routing on the server itself.
Try to tracert from the machine you are trying to connect to and from the server itself and compare routes.
+ see which router responds "Host Unreachable"