Interface Config

This is my Interfaceconfig for one IP4-Address.
You can change your Config via nano or vim. After making changes, you should restart the server

nano /etc/network/interfaces
reboot

# network interface settings; autogenerated
# Please do NOT modify this file directly, unless you know what
# you're doing.
#
# If you want to manage parts of the network configuration manually,
# please utilize the 'source' or 'source-directory' directives to do
# so.
# PVE will preserve these directives, but will NOT read its network
# configuration from sourced files, so do not attempt to move any of
# the PVE managed interfaces into external files!

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

iface lo inet6 loopback

auto eno1
iface eno1 inet static
        address <YOUR_IP4_ADDRESS>
        gateway <YOUR_IP4_GATEWAY>
        post-up sysctl -w net.ipv4.ip_forward=1
        post-up iptables -t nat -A PREROUTING -i eno1 -p tcp -m multiport ! --dport 22,8006 -j DNAT --to 10.10.10.1
        post-up iptables -t nat -A PREROUTING -i eno1 -p udp -j DNAT --to 10.10.10.1

iface eno1 inet6 static
        address <YOUR_IP6_ADDRESS>
        gateway <YOUR_IP6_GATEWAY>

auto vmbr0
iface vmbr0 inet static
        address 10.10.10.0/31
        bridge-ports none
        bridge-stp off
        bridge-fd 0
        post-up iptables -t nat -A POSTROUTING -s '10.10.10.1/31' -o eno1 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s '10.10.10.1/31' -o eno1 -j MASQUERADE
#OPN-Sense WAN

auto vmbr1
iface vmbr1 inet manual
        bridge-ports none
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        ovs_type OVSBridge
#VLAN-Network

What did i configure?

All Requests to the server except on port 22(SSH) and 8006(proxmox) will get redirected to the opnsense (static IP).
I only configured IPv4 you can also setup it for IPv6 if needed