Proxmox and pfSense/OPNsense Configuration with Single IP

readme.md

Enable System IP forwarding first

echo 'net.ipv4.ip_forward = 1' | sudo tee -a /etc/sysctl.conf
echo 'net.ipv6.conf.all.forwarding = 1' | sudo tee -a /etc/sysctl.conf
sudo sysctl -p /etc/sysctl.conf

Here is sample network configuration (remove comments "##") Replace your interface name, public IP, internal NAT IP

auto vmbr0
iface vmbr0 inet static
        address XX.YY.ZZ.IP/AB
        gateway XX.YY.ZZ.GW
        bridge-ports enp0s25
        bridge-stp off
        bridge-fd 0
        post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp -m multiport ! --dport 22,8006 -j DNAT --to-destination 192.168.2.2
        post-up iptables -t nat -A PREROUTING -i vmbr0 -p udp -m multiport ! --dport 22,8006 -j DNAT --to-destination 192.168.2.2
        post-down iptables -t nat -D PREROUTING -i vmbr0 -p tcp -m multiport ! --dport 22,8006 -j DNAT --to-destination 192.168.2.2
        post-down iptables -t nat -D PREROUTING -i vmbr0 -p udp -m multiport ! --dport 22,8006 -j DNAT --to-destination 192.168.2.2
#Host Network

iface vmbr0 inet6 static
        address XX:YY:ZZ::IP/AB
        gateway XX:YY:ZZ::GW

auto vmbr1
iface vmbr1 inet static
        address 192.168.2.1/24
        bridge-ports none
        bridge-stp off
        bridge-fd 0
        post-up iptables -t nat -A POSTROUTING -s 192.168.2.0/24 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s 192.168.2.0/24 -j MASQUERADE
#NAT Lan

auto vmbr2
iface vmbr2 inet manual
        bridge-ports none
        bridge-stp off
        bridge-fd 0
#pfSense LAN