Problems with 2nd IP

[Patrick-72]

Hi,

i have Proxmox running with OPNSense and several other VM´s.

I can connect to Proxmox WEB, OPNSense and the VM´s behind the OPNSense.

Now i have a second IP for another single VM, but i´m not able to get it running.

This is my Network setting without the Second IP:

source /etc/network/interfaces.d/*

auto lo
iface lo inet loopback

iface lo inet6 loopback

#Physikalische Schnittstelle mit Haupt-IP
auto enp5s0
iface enp5s0 inet static
        address 123.89.12.17/32
        gateway 123.89.12.1
        up route add -net 123.89.12.17 netmask 255.255.255.255 gw 123.89.12.1 dev enp5s0
        post-up   echo 1 > /proc/sys/net/ipv4/ip_forward
        post-up sysctl -w net.ipv4.ip_forward=1
        post-up iptables -t nat -A PREROUTING -i enp5s0 -p tcp -m multiport ! --dport 22,8006 -j DNAT --to 192.168.0.2
        post-up iptables -t nat -A PREROUTING -i enp5s0 -p udp -j DNAT --to 192.168.0.2

iface enp5s0 inet6 static
        address xxxxxxxxxxxxxxxx
        gateway fe80::1

iface eth0 inet manual

#Virtuelle Schnittstelle zur Verwendung der zweiten IP 123.89.12.11
auto vmbr0
iface vmbr0 inet static
        bridge-ports none
        bridge-stp off
        bridge-fd 0

#Virtuelle Schnittstelle zur OPNSense
auto vmbr1
iface vmbr1 inet static
        address 192.168.0.1/30
        bridge-ports none
        bridge-stp off
        bridge-fd 0
        post-up iptables -t nat -A POSTROUTING -s '192.168.0.0/30' -o enp5s0 -j MASQUERADE
        post-down iptables -t nat -D POSTROUTING -s '192.168.0.0/30' -o enp5s0 -j MASQUERADE

#Virtuelle Schnittstelle für internes Netzwerk hinter der OPNSense (VM-Netzwerk)
auto vmbr2
iface vmbr2 inet manual
        bridge-ports none
        bridge-stp off
        bridge-fd 0

I tried every "solution" i found with google, but it won´t work.
How do i have to configure my Proxmox Network and the single VM for the 2nd IP?

Thanks
Patrick