Weird Connectivity Issue

[weubjndsknpen]

I have a basic setup with what is essentially a bridged host-only network on 192.168.56.0/24.

I've got 5 Windows servers on that network.
192.168.56.10
192.168.56.11
192.168.56.12
192.168.56.22
192.168.56.23

I can ping them all from the proxmox host.
They can all ping each other.

I've got one Ubuntu server on that subnet.
192.168.56.30

It can ping the windows servers.
They can ping it.
They can connect to it on ssh.

I cannot ping the Ubuntu server from the proxmox host, but get an error about how the host is unreachable.

root@pve:~# ip route get 192.168.56.10
192.168.56.10 dev vmbr1 src 192.168.56.0 uid 0
cache
root@pve:~# ip route get 192.168.56.30
192.168.56.30 dev vmbr1 src 192.168.56.0 uid 0
cache
------------------------------------------------------------------------------------------------------------
root@pve:~# ping 192.168.56.10
PING 192.168.56.10 (192.168.56.10) 56(84) bytes of data.
64 bytes from 192.168.56.10: icmp_seq=1 ttl=128 time=0.208 ms
^C
--- 192.168.56.10 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.208/0.208/0.208/0.000 ms
root@pve:~# ping 192.168.56.30
PING 192.168.56.30 (192.168.56.30) 56(84) bytes of data.
From 192.168.56.0 icmp_seq=1 Destination Host Unreachable

Any ideas would be appreciated.

UFW is off on Ubuntu and I flushed iptables rules.

 

[Hannes Laimer]

Hey,

weird indeed. Maybe some netmask is set incorrectly, could you post ip a from PVE and Ubuntu? Did you do some kernel update lately? Not restarting after a kernel update sometimes causes weird issues.

 

[bobmc]

I don't think 192.168.56.0 is a valid IP address for the host - only 1-254 are allowed, .0 and .255 are reserved