Proxmox - containers behind NAT do not have internet access, why?

Question

Debian

Hello, I have such a network config in proxmox, vmbr0 interface has Internet access, vmbr1 internal virtual sit down, I'm trying to set up masquerading from network 10.0.0.0/24. - unknown host, HOST restarted the machine, nothing has changed, where did I screw up?
HOST NETWORK CONFIG

auto vmbr1
iface vmbr1 inet static
        address  10.0.0.1
        netmask  255.255.255.0
        bridge_ports dummy0
        bridge_stp off
        bridge_fd 0
        post-up /etc/pve/kvm-networking.sh
        post-up echo 1 > /proc/sys/net/ipv4/ip_forward
        post-up iptables -t nat -A POSTROUTING -o vmbr0 -j MASQUERADE
        post-up iptables -t nat -A POSTROUTING -s '10.0.0.0/24' -o vmbr0 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s '10.0.0.0/24' -o vmbr0 -j MASQUERADE

auto vmbr0
iface vmbr0 inet static
        address  [IP HOST ]
        netmask  255.255.255.0
        gateway  [GATEWAY HOST]
        broadcast  [BROADCAST HOST]
        bridge_ports eth0
        bridge_stp off
        bridge_fd 0
        network [NETWORK]

iface vmbr0 inet6 static
        address  [ADRESS]
        netmask  64
        post-up /sbin/ip -f inet6 route add 2001: dev vmbr0
        post-up /sbin/ip -f inet6 route add default via 2001:
        pre-down /sbin/ip -f inet6 route del default via 2001:
        pre-down /sbin/ip -f inet6 route del 2001 dev vmbr0

GUEST NETWORK CONFIG

adress - 10.0.0.50
mask - 255.255.255.0
gateway - 10.0.0.1

Answer 1

The question can be closed, for some reason /proc/sys/net/ipv4/ip_forward was set to 0