Routing public IPv4s to local VMs

I wanted to assign real, routable IPv4 addresses to hosts behind my pfSense firewall at home. The catch? I'm behind CGNAT, so I can't just port-forward or announce my own ranges. Instead, I used a cheap VPS as a router and passed secondary IPv4s over WireGuard into my homelab. The result: my VMs get public IPs, just like they were on the VPS directly.

This post is a rough walkthrough of what I did - not a professional guide, but enough that someone else could follow along.

Why even bother?

I wanted real public IPv4s on my internal VMs (mainly for Minecraft server hosting).
I'm stuck behind CGNAT, so I can't get inbound connections otherwise.
I didn't want to run everything directly on the VPS - I wanted to leverage the compute I have locally.

With this, traffic for my secondary IPs hits the VPS first, then gets shoved over WireGuard into pfSense. pfSense "owns" those IPs and can hand them off to internal hosts. These hosts will see the public /32 IP as their own; it's not even behind a 1:1 NAT.

Latency considerations

You're essentially hairpinning your traffic through a VPS, so pick one as close as possible.

Example numbers from my setup, after trying some local VPS providers:

I have around 7-8ms ping to my ISP's gateway
This means 11ms ping to 1.1.1.1 directly
My VPS has 11ms latency from home and only 2ms latency to 1.1.1.1
Traceroutes are also really short

The end result for my setup: 14-15ms ping to 1.1.1.1 after inserting the VPS into the path. That's pretty acceptable for me.

IP plan I used

Swapped for RFC 1918 private and RFC 5737 documentation addresses, used throughout this tutorial:

10.99.0.0/30 -> WireGuard tunnel network
10.99.0.1 -> VPS WireGuard side
10.99.0.2 -> pfSense WireGuard side
203.0.113.10 -> VPS primary IP
203.0.113.55 -> VPS secondary IP (will end up on a VM behind pfSense)

VPS configuration

The VPS has pretty much a normal WireGuard setup. My /etc/wireguard/wg0.conf looked like this:

[Interface]
PrivateKey = ...
Address = 10.99.0.1/32
ListenPort = 51820

[Peer]
PublicKey = ...
AllowedIPs = 10.99.0.2/32, 203.0.113.55/32

Note that 203.0.113.55/32 (the IP(s) that you want to pass to internal hosts) is included in AllowedIPs.

Enable + start WireGuard:

systemctl enable wg-quick@wg0
systemctl start wg-quick@wg0

Enable forwarding + tweak kernel settings

Create /etc/sysctl.d/99-wg-router.conf:

# Forwarding
net.ipv4.ip_forward=1

# Reverse-path filtering: loose mode
net.ipv4.conf.all.rp_filter=2
net.ipv4.conf.default.rp_filter=2
net.ipv4.conf.eth0.rp_filter=2
net.ipv4.conf.wg0.rp_filter=2

Proxy ARP for secondary IPs

My provider gave me a /24 with 203.0.113.10 as primary, plus 203.0.113.55 as a secondary. Their router expects to see ARP replies for .55. So I had to enable proxy_arp on my VPS:

# We're proxy-ARPing on an on-link /24
net.ipv4.conf.eth0.proxy_arp=1

In the same file.

Apply everything:

sysctl --system

pfSense configuration

On the pfSense side, create the WireGuard tunnel:

Address: 10.99.0.2/30

Configure the WireGuard peer:

AllowedIPs: 0.0.0.0/0 (important - you want all traffic destined for your secondary IPs to pass through)

Create a WireGuard interface:

Static IPv4: 10.99.0.2/30
MTU: 1420

Set up a gateway:

Address: 10.99.0.1
Call it something like vwan_gateway Back in the interface settings, mark that gateway as the IPv4 upstream.

Quick test

Add the public IP (203.0.113.55/32) as a virtual IP on the WireGuard interface. Allow ICMP to it.

If everything's right:

You can ping 203.0.113.55 from outside.
pfSense replies.
Latency should match what you expect (VPS + tunnel overhead).

If not, debug from the VPS with:

tcpdump -ni eth0 'icmp and host 203.0.113.55'
tcpdump -ni wg0 'icmp and host 203.0.113.55'

Assigning the public IP to a VM behind pfSense

Now let's put that secondary IP on an internal host.

On the VM

Check its existing LAN config:

ip addr
ip route

Temporarily assign the public IP:

sudo ip addr add 203.0.113.55/32 dev ens18

sudo ip route del default
sudo ip route add default via <original LAN gateway> dev ens18 src 203.0.113.55

Or make it permanent with netplan:

network:
  version: 2
  ethernets:
    ens18:
      dhcp4: false
      addresses:
        - <original LAN address>/24
        - 203.0.113.55/32
      routes:
        - to: 0.0.0.0/0
          via: <original LAN gateway>
          from: 203.0.113.55

Back in pfSense

Add a gateway (e.g. vwan_internal_55):

Gateway address = the host's original LAN IP

Create a static route:

203.0.113.55 → vwan_internal_55

Add a LAN rule:

Match source 203.0.113.55, destination * (or any stricter WAN rule you might have)
Advanced settings: gateway = vwan_gateway
Make sure this rule is above your general LAN rules.

Note: Once your VM is using the public IP, it no longer matches your "LAN subnet" rules. If you have existing allow rules, you'll need to duplicate them to also cover 203.0.113.55. At this point there will also be no firewall to block anything going to 203.0.113.55 - it'll go straight to your VM.

Adding more public IPv4's

To add more public IPv4's to other internal hosts, just go through every step and repeat or add to each step referencing 203.0.113.55. A high-level overview to add another IP (203.0.113.60):

Add 203.0.113.60 to AllowedIPs in the VPS's WireGuard config.
Add 203.0.113.60 to a second internal VM, just like described in the steps above.
Add a second gateway in pfsense - vwan_internal_60 pointing to the second VMs internal address.
Add a second static route - 203.0.113.60 -> vwan_internal_60
Update LAN rules accordingly.

Closing notes

That's it - now you’ve got a host behind pfSense using a VPS's secondary public IPv4 like it was directly on the internet. This works even behind CGNAT.

But keep in mind, you don't get a firewall for free anymore. Traffic comes straight to your host. You'll need to manage this yourself - either in pfSense or on the VM (UFW, nftables, iptables, etc.).

Routing public IPv4s to local VMs, through a VPS & pfSense with WireGuard