How to configure firewall in proxmox?

Good time of day.
I can not understand how to properly configure the firewall in Proxmox.
This:
1)Proxmox Server at hetzner.
On the server I created two bridge:
  • vmbr0 for virtualos with external ip
  • vmbr1 for virtualos with the local ip. are behind a NAT. hear the ip from the dhcp server.(like 192.168.12.xxx)

There's a dev with a shared folder with ip 192.168.12.2.
2)office with a mikrotik router.
3) Between the office and the server proxmox raised gre tunnel.

When turned off firewall.
From the office ping 192.168.12.2 and the share is available.
Question. How can pingomatic 192.168.12.2 if it is behind a NAT?

If you have enabled firewall policy INPUT DROP
From the office don'T ping 192.168.12.2 shared folder is NOT available.
Question. What is the rule it is necessary to register in the firewall to 192.168.12.2 available from the office network?

I suspect that you have enabled the firewall cut gre traffic.
But
iptables-I INPUT-p gre -j ACCEPT
not solve the problem.
June 14th 19 at 18:13
0 answer

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