Proxmox - /etc/network/interfaces Working

$ cat /etc/network/interfaces
### Hetzner Online GmbH installimage

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback
iface lo inet6 loopback

auto eno1
iface eno1 inet static
  address <public_ip>
  netmask 255.255.255.224
  gateway 145.250.76.33
  # route 145.250.76.32/27 via 145.250.76.33
  up route add -net 145.250.76.32 netmask 255.255.255.224 gw 145.250.76.33 dev eno1
  up ip link set eno1 txqueuelen 10000

iface eno1 inet6 static
  address 2b01:4f8:212:4138::2
  netmask 64
  gateway fe71::1

auto vmbr2
iface vmbr2 inet static
  address 192.168.22.254
  netmask 255.255.255.0
  bridge_ports none
  bridge_stp off
  bridge_fd 0
  up ip link set vmbr2 txqueuelen 10000
  post-up echo 1 > /proc/sys/net/ipv4/ip_forward
  post-up echo 1 > /proc/sys/net/ipv4/conf/vmbr2/proxy_arp
  ### MASQUERADE RULE
  post-up iptables -t nat -A POSTROUTING -o eno1 -j MASQUERADE --source '192.168.22.0/24'
  ### SSH PREROUTING rules on both interfaces
  post-up iptables -t nat -A PREROUTING -i eno1 -p tcp --dport 2222 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:22
  post-up iptables -t nat -A PREROUTING -i vmbr2 -p tcp --dport 2222 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:22
  ### HTTP PREROUTING rules on both interfaces
  post-up iptables -t nat -A PREROUTING -i eno1 -p tcp --dport 80 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:80
  post-up iptables -t nat -A PREROUTING -i vmbr2 -p tcp --dport 80 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:80
  ### HTTPS PREROUTING rules on both interfaces
  post-up iptables -t nat -A PREROUTING -i eno1 -p tcp --dport 443 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:443
  post-up iptables -t nat -A PREROUTING -i vmbr2 -p tcp --dport 443 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:443
  ### OUTPUT rules
  post-up iptables -t nat -A OUTPUT -p tcp --dport 80 -j DNAT --destination <public_ip>/32 --to-destination 192.168.22.5:80
  post-up iptables -t nat -A OUTPUT -p tcp --dport 443 -j DNAT --destination <public_ip>/32 --to-destination 192.168.22.5:443
  post-up iptables -t nat -A OUTPUT -p tcp --dport 2222 -j DNAT --destination <public_ip>/32 --to-destination 192.168.22.5:22
  #### DOWN rules to remove all rules from above. ####
  post-down iptables -t nat -D POSTROUTING -o eno1 -j MASQUERADE --source '192.168.22.0/24'
  post-down iptables -t nat -D PREROUTING -i eno1 -p tcp --dport 2222 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:22
  post-down iptables -t nat -D PREROUTING -i vmbr2 -p tcp --dport 2222 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:22
  post-down iptables -t nat -D PREROUTING -i eno1 -p tcp --dport 80 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:80
  post-down iptables -t nat -D PREROUTING -i vmbr2 -p tcp --dport 80 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:80
  post-down iptables -t nat -D PREROUTING -i eno1 -p tcp --dport 443 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:443
  post-down iptables -t nat -D PREROUTING -i vmbr2 -p tcp --dport 443 -j DNAT --destination <public_ip> --to-destination 192.168.22.5:443
  post-down iptables -t nat -D OUTPUT -p tcp --dport 80 -j DNAT --destination <public_ip>/32 --to-destination 192.168.22.5:80
  post-down iptables -t nat -D OUTPUT -p tcp --dport 443 -j DNAT --destination <public_ip>/32 --to-destination 192.168.22.5:443
  post-down iptables -t nat -D OUTPUT -p tcp --dport 2222 -j DNAT --destination <public_ip>/32 --to-destination 192.168.22.5:22