Public addresses on Proxmox through the bridge, why it can fly out through the defined. time?

Question

linux

Need community help, configured ProxMox on Debian 10, bought about 20 public addresses, all of them were bound to eth0 by default, below is how it was configured by default, I give an example with 1 address:

# The loopback network interface

auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
auto eth0
iface eth0 inet static
        address xx.yyy.162.143/23
        gateway xx.yyy.162.1
        # dns-* options are implemented by the resolvconf package, if installed
        dns-nameservers 1.1.1.1
        dns-search mydomain.com
        
auto eth0:1
allow-hotplug eth0:1
iface eth0:1 inet static
  address xx.yyy.163.84
  netmask 255.255.255.255

After that, I reconfigured it in this way (the number of bridges is equal to the number of public addresses, in the example, again, only one):

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0
auto eth0
iface eth0 inet static
        address xx.yyy.162.143/23
        gateway xx.yyy.162.1
        # dns-* options are implemented by the resolvconf package, if installed
        dns-nameservers 1.1.1.1
        dns-search mydomain.com

auto vmbr1084
iface vmbr1084  inet static
 address xx.yyy.162.143
 netmask 255.255.254.0
 bridge-ports none
 bridge-stp off
 bridge-fd 0
 bridge_maxwait 0
 up ip route add xx.yyy.163.84/32 dev vmbr1084
 down ip route delete xx.yyy.163.84/32 dev vmbr1084
#Ext-84 [xx.yyy.163.84]

Inside the virtual machine, it is configured like this, in the Windows Server example (using a point-to-point link):

IP: xx.yyy.163.84
NET: 255.255.255.255
GW: xx.yyy.162.143

Everything works fine, but not for long, sometimes 1 hour, sometimes 4 hours, there are not a lot of logs, maybe I don’t know where to look, the configuration as a whole does not change.
Symptoms - everything just stops working, access is lost anywhere from inside the VM, outside too.
At the same time, I see arp request / arp reply from the inside, but there is an arp request from the host machine, but arp replay does not return, everything seems to be ok in the arp cache.
I don't even know which way to dig.
When resetting network interfaces, everything starts working again, but again a random amount of time.
I would be grateful for any advice.

uname -a
Linux myhostname 5.3.18-3-pve #1 SMP PVE 5.3.18-3 (Tue, 17 Mar 2020 16:33:19 +0100) x86_64 GNU/Linux

Answer 1

On the host, you do not need to add additional. addresses if it is not host-routed. It is enough to configure on the guest.

Answer 2

Maybe try adding another virtual machine for example with pfsense and use it as a gateway and safer and snort there is well, like protection from a hostile Internet and most importantly there is a multi van in my answers there was an instruction how to forward a specific white ip (out of several) to network behind nat well to other virtual machines.

Answer 3

Syslog look and dmesg