f3s: Kubernetes with FreeBSD - Part 5: WireGuard mesh network

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f3s: Kubernetes with FreeBSD - Part 5: WireGuard mesh network
⇢ Introduction
⇢ ⇢ Expected traffic flow
⇢ Deciding on WireGuard
⇢ Base configuration
⇢ ⇢ FreeBSD
⇢ ⇢ Rocky Linux
⇢ ⇢ OpenBSD
⇢ WireGuard configuration
⇢ ⇢ Example wg0.conf
⇢ ⇢ NAT traversal and keepalive
⇢ ⇢ Preshared key
⇢ Mesh network generator
⇢ ⇢ wireguardmeshgenerator.yaml
⇢ ⇢ wireguardmeshgenerator.rb overview
⇢ Invoking the mesh network generator
⇢ ⇢ Generating the wg0.conf files and keys
⇢ ⇢ Installing the wg0.conf files
⇢ ⇢ Re-generating mesh and installing the wg0.conf files again
⇢ ⇢ Setting up roaming clients
⇢ Adding IPv6 support to the mesh
⇢ ⇢ IPv6 addressing scheme
⇢ ⇢ Updating the mesh generator for IPv6
⇢ ⇢ IPv6 NAT on OpenBSD gateways
⇢ ⇢ Manual OpenBSD interface configuration
⇢ ⇢ Verifying dual-stack connectivity
⇢ Happy WireGuard-ing
⇢ Managing Roaming Client Tunnels
⇢ ⇢ Manual gateway failover configuration
⇢ ⇢ Starting and stopping on earth (Fedora laptop)
⇢ ⇢ Starting and stopping on pixel7pro (Android phone)
⇢ ⇢ Verifying connectivity
⇢ Conclusion

Introduction

By default, traffic within my home LAN, including traffic inside a k3s cluster, is not encrypted. It's in the "secure" home LAN, but I'd rather not trust the LAN (zero trust and all that), so it should be encrypted anyway. So we decide to secure all the traffic of all f3s participating hosts by building a mesh network:

The mesh network consists of eight infrastructure hosts and two roaming clients:

Infrastructure hosts (full mesh):

f0, f1, and f2 are the FreeBSD base hosts in my home LAN
r0, r1, and r2 are the Rocky Linux Bhyve VMs running on the FreeBSD hosts
blowfish and fishfinger are two OpenBSD systems running on the internet (as mentioned in the first blog of this series—these systems are already built; in fact, this very blog is served by those OpenBSD systems)

oaming clients (gateway-only connections):

earth is my Fedora laptop (192.168.2.200) which connects only to the internet gateways for remote access
pixel7pro is my Android phone (192.168.2.201) which routes all traffic through the VPN when activated

As we can see from the diagram, the eight infrastructure hosts form a true full-mesh network, where every host has a VPN tunnel to every other host. The benefit is that we do not need to route traffic through intermediate hosts (significantly simplifying the routing configuration). However, the downside is that there is some overhead in configuring and managing all the tunnels. The roaming clients take a simpler approach—they only connect to the two internet-facing gateways (blowfish and fishfinger), which is sufficient for remote access and internet connectivity.

For simplicity, we also establish VPN tunnels between f0 <-> r0, f1 <-> r1, and f2 <-> r2. Technically, this wouldn't be strictly required since the VMs rN are running on the hosts fN, and no network traffic is leaving the box. However, it simplifies the configuration as we don't have to account for exceptions, and we are going to automate the mesh network configuration anyway (read on).

Expected traffic flow

The traffic is expected to flow between the host groups through the mesh network as follows:

nfrastructure mesh traffic:

fN <-> rN: The traffic between the FreeBSD hosts and the Rocky Linux VMs will be routed through the VPN tunnels for persistent storage. In a later post in this series, we will set up an NFS server on the fN hosts.
fN <-> blowfish,fishfinger: The traffic between the FreeBSD hosts and the OpenBSD host blowfish,fishfinger will be routed through the VPN tunnels for management. We may want to log in via the internet to set it up remotely. The VPN tunnel will also be used for monitoring purposes.
rN <-> blowfish,fishfinger: The traffic between the Rocky Linux VMs and the OpenBSD host blowfish,fishfinger will be routed through the VPN tunnels for usage traffic. Since k3s will be running on the rN hosts, the OpenBSD servers will route the traffic through relayd to the services running in Kubernetes.
fN <-> fM: The traffic between the FreeBSD hosts may be later used for data replication for the NFS storage.
rN <-> rM: The traffic between the Rocky Linux VMs will later be used by the k3s cluster itself, as every rN will be a Kubernetes worker node.
blowfish <-> fishfinger: The traffic between the OpenBSD hosts isn't strictly required for this setup, but I set it up anyway for future use cases.

oaming client traffic:

earth,pixel7pro <-> blowfish,fishfinger: The roaming clients connect exclusively to the two internet gateways. All traffic from these clients (0.0.0.0/0) is routed through the VPN, providing secure internet access and the ability to reach services running in the mesh (via the gateways). The gateways use NAT to allow roaming clients to access the internet using the gateway's public IP address. The roaming clients cannot be reached by the LAN hosts—they are client-only and initiate all connections.

We won't cover all the details in this blog post, as we only focus on setting up the Mesh network in this blog post. Subsequent posts in this series will cover the other details.

Deciding on WireGuard

I have decided to use WireGuard as the VPN technology for this purpose.

WireGuard is a small, modern VPN protocol. The codebase is tiny, the configuration is simple, and it's fast. It's available on FreeBSD, Linux, and OpenBSD, and the implementations talk to each other, which is exactly what I need here.

We could have used Tailscale for an easy to set up and manage the WireGuard network, but the benefits of creating our own mesh network are:

Learning about WireGuard configuration details
Have full control over the setup
Don't rely on an external provider like Tailscale (even if some of the components are open-source)
Have even more fun along the way
WireGuard is easy to configure on my target operating systems and, therefore, easier to maintain in the long run.
There are no official Tailscale packages available for OpenBSD and FreeBSD. However, getting Tailscale running on these systems is still possible, though some tinkering would be required. Instead, we use that tinkering time to set up WireGuard tunnels ourselves.

https://en.wikipedia.org/wiki/WireGuard
https://www.wireguard.com/
https://tailscale.com/

Base configuration

In the following, we prepare the base configuration for the WireGuard mesh network. We will use a similar configuration on all participating hosts, with the exception of the host IP addresses and the private keys.

FreeBSD

On the FreeBSD hosts f0, f1 and f2, similar as last time, first, we bring the system up to date:

paul@f0:~ % doas freebsd-update fetch
paul@f0:~ % doas freebsd-update install
paul@f0:~ % doas shutdown -r now
..
..
paul@f0:~ % doas pkg update
paul@f0:~ % doas pkg upgrade
paul@f0:~ % reboot

Next, we install wireguard-tools and configure the WireGuard service:

paul@f0:~ % doas pkg install wireguard-tools
paul@f0:~ % doas sysrc wireguard_interfaces=wg0
wireguard_interfaces:  -> wg0
paul@f0:~ % doas sysrc wireguard_enable=YES
wireguard_enable:  -> YES
paul@f0:~ % doas mkdir -p /usr/local/etc/wireguard
paul@f0:~ % doas touch /usr/local/etc/wireguard/wg0.conf
paul@f0:~ % doas service wireguard start
paul@f0:~ % doas wg show
interface: wg0
  public key: L+V9o0fNYkMVKNqsX7spBzD/9oSvxM/C7ZCZX1jLO3Q=
  private key: (hidden)
  listening port: 20246

We now have the WireGuard up and running, but it is not yet in any functional configuration. We will come back to that later.

Next, we add all the participating WireGuard IPs to the hosts file. This is only convenience, so we don't have to manage an external DNS server for this:

paul@f0:~ % cat <<END | doas tee -a /etc/hosts

192.168.1.120 r0 r0.lan r0.lan.buetow.org
192.168.1.121 r1 r1.lan r1.lan.buetow.org
192.168.1.122 r2 r2.lan r2.lan.buetow.org

192.168.2.130 f0.wg0 f0.wg0.wan.buetow.org
192.168.2.131 f1.wg0 f1.wg0.wan.buetow.org
192.168.2.132 f2.wg0 f2.wg0.wan.buetow.org

192.168.2.120 r0.wg0 r0.wg0.wan.buetow.org
192.168.2.121 r1.wg0 r1.wg0.wan.buetow.org
192.168.2.122 r2.wg0 r2.wg0.wan.buetow.org

192.168.2.110 blowfish.wg0 blowfish.wg0.wan.buetow.org
192.168.2.111 fishfinger.wg0 fishfinger.wg0.wan.buetow.org

fd42:beef:cafe:2::130 f0.wg0 f0.wg0.wan.buetow.org
fd42:beef:cafe:2::131 f1.wg0 f1.wg0.wan.buetow.org
fd42:beef:cafe:2::132 f2.wg0 f2.wg0.wan.buetow.org

fd42:beef:cafe:2::120 r0.wg0 r0.wg0.wan.buetow.org
fd42:beef:cafe:2::121 r1.wg0 r1.wg0.wan.buetow.org
fd42:beef:cafe:2::122 r2.wg0 r2.wg0.wan.buetow.org

fd42:beef:cafe:2::110 blowfish.wg0 blowfish.wg0.wan.buetow.org
fd42:beef:cafe:2::111 fishfinger.wg0 fishfinger.wg0.wan.buetow.org
END

As you can see, 192.168.1.0/24 is the network used in my LAN (with the fN and rN hosts) and 192.168.2.0/24 is the network used for the WireGuard mesh network. The wg0 interface will be used for all WireGuard traffic.

Rocky Linux

We bring the Rocky Linux VMs up to date as well with the following:

[root@r0 ~] dnf update -y
[root@r0 ~] reboot

Next, we prepare WireGuard on them. Same as on the FreeBSD hosts, we will only prepare WireGuard without any useful configuration yet:

[root@r0 ~] dnf install -y wireguard-tools
[root@r0 ~] mkdir -p /etc/wireguard
[root@r0 ~] touch /etc/wireguard/wg0.conf
[root@r0 ~] systemctl enable wg-quick@wg0.service
[root@r0 ~] systemctl start wg-quick@wg0.service
[root@r0 ~] systemctl disable firewalld

We also update the hosts file accordingly:

[root@r0 ~] cat <<END >>/etc/hosts

192.168.1.130 f0 f0.lan f0.lan.buetow.org
192.168.1.131 f1 f1.lan f1.lan.buetow.org
192.168.1.132 f2 f2.lan f2.lan.buetow.org

192.168.2.130 f0.wg0 f0.wg0.wan.buetow.org
192.168.2.131 f1.wg0 f1.wg0.wan.buetow.org
192.168.2.132 f2.wg0 f2.wg0.wan.buetow.org

192.168.2.120 r0.wg0 r0.wg0.wan.buetow.org
192.168.2.121 r1.wg0 r1.wg0.wan.buetow.org
192.168.2.122 r2.wg0 r2.wg0.wan.buetow.org

192.168.2.110 blowfish.wg0 blowfish.wg0.wan.buetow.org
192.168.2.111 fishfinger.wg0 fishfinger.wg0.wan.buetow.org

fd42:beef:cafe:2::130 f0.wg0 f0.wg0.wan.buetow.org
fd42:beef:cafe:2::131 f1.wg0 f1.wg0.wan.buetow.org
fd42:beef:cafe:2::132 f2.wg0 f2.wg0.wan.buetow.org

fd42:beef:cafe:2::120 r0.wg0 r0.wg0.wan.buetow.org
fd42:beef:cafe:2::121 r1.wg0 r1.wg0.wan.buetow.org
fd42:beef:cafe:2::122 r2.wg0 r2.wg0.wan.buetow.org

fd42:beef:cafe:2::110 blowfish.wg0 blowfish.wg0.wan.buetow.org
fd42:beef:cafe:2::111 fishfinger.wg0 fishfinger.wg0.wan.buetow.org
END

Unfortunately, the SELinux policy on Rocky Linux blocks WireGuard's operation. By making the wireguard_t domain permissive using semanage permissive -a wireguard_t, SELinux will no longer enforce restrictions for WireGuard, allowing it to work as intended:

[root@r0 ~] dnf install -y policycoreutils-python-utils
[root@r0 ~] semanage permissive -a wireguard_t
[root@r0 ~] reboot

https://github.com/angristan/wireguard-install/discussions/499

OpenBSD

Other than the FreeBSD and Rocky Linux hosts involved, my OpenBSD hosts (blowfish and fishfinger, which are running at OpenBSD Amsterdam and Hetzner on the internet) have been running already for longer, so I can't provide you with the "from scratch" installation details here. In the following, we will only focus on the additional configuration needed to set up WireGuard:

blowfish$ doas pkg_add wireguard-tools
blowfish$ doas mkdir /etc/wireguard
blowfish$ doas touch /etc/wireguard/wg0.conf
blowsish$ cat <<END | doas tee /etc/hostname.wg0
inet 192.168.2.110 255.255.255.0 NONE
up
!/usr/local/bin/wg setconf wg0 /etc/wireguard/wg0.conf
END

Note that on blowfish, we configure 192.168.2.110 here in the hostname.wg, and on fishfinger, we configure 192.168.2.111. Those are the IP addresses of the WireGuard interfaces on those hosts.

And here, we also update the hosts file accordingly:

blowfish$ cat <<END | doas tee -a /etc/hosts

192.168.2.130 f0.wg0 f0.wg0.wan.buetow.org
192.168.2.131 f1.wg0 f1.wg0.wan.buetow.org
192.168.2.132 f2.wg0 f2.wg0.wan.buetow.org

192.168.2.120 r0.wg0 r0.wg0.wan.buetow.org
192.168.2.121 r1.wg0 r1.wg0.wan.buetow.org
192.168.2.122 r2.wg0 r2.wg0.wan.buetow.org

192.168.2.110 blowfish.wg0 blowfish.wg0.wan.buetow.org
192.168.2.111 fishfinger.wg0 fishfinger.wg0.wan.buetow.org
192.168.2.200 earth.wg0 earth.wg0.wan.buetow.org
192.168.2.201 pixel7pro.wg0 pixel7pro.wg0.wan.buetow.org

fd42:beef:cafe:2::130 f0.wg0 f0.wg0.wan.buetow.org
fd42:beef:cafe:2::131 f1.wg0 f1.wg0.wan.buetow.org
fd42:beef:cafe:2::132 f2.wg0 f2.wg0.wan.buetow.org

fd42:beef:cafe:2::120 r0.wg0 r0.wg0.wan.buetow.org
fd42:beef:cafe:2::121 r1.wg0 r1.wg0.wan.buetow.org
fd42:beef:cafe:2::122 r2.wg0 r2.wg0.wan.buetow.org

fd42:beef:cafe:2::110 blowfish.wg0 blowfish.wg0.wan.buetow.org
fd42:beef:cafe:2::111 fishfinger.wg0 fishfinger.wg0.wan.buetow.org
fd42:beef:cafe:2::200 earth.wg0 earth.wg0.wan.buetow.org
fd42:beef:cafe:2::201 pixel7pro.wg0 pixel7pro.wg0.wan.buetow.org
END

To enable roaming clients (like earth and pixel7pro) to access the internet through the VPN, we need to configure NAT on the OpenBSD gateways. This allows the roaming clients to use the gateway's public IP address for outbound traffic. We add the following to /etc/pf.conf on both blowfish and fishfinger:

# NAT for WireGuard clients to access internet
match out on vio0 from 192.168.2.0/24 to any nat-to (vio0)

# Allow inbound traffic on WireGuard interface
pass in on wg0

# Allow all UDP traffic on WireGuard port
pass in inet proto udp from any to any port 56709

After updating /etc/pf.conf, reload the firewall:

blowfish$ doas pfctl -f /etc/pf.conf

WireGuard configuration

So far, we have only started WireGuard on all participating hosts without any useful configuration. This means that no VPN tunnel has been established yet between any of the hosts.

Example wg0.conf

Generally speaking, a wg0.conf looks like this (example from f0 host):

[Interface]
# f0.wg0.wan.buetow.org
Address = 192.168.2.130
PrivateKey = **************************
ListenPort = 56709

[Peer]
# f1.lan.buetow.org as f1.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 192.168.2.131/32
Endpoint = 192.168.1.131:56709
# No KeepAlive configured

[Peer]
# f2.lan.buetow.org as f2.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 192.168.2.132/32
Endpoint = 192.168.1.132:56709
# No KeepAlive configured

[Peer]
# r0.lan.buetow.org as r0.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 192.168.2.120/32
Endpoint = 192.168.1.120:56709
# No KeepAlive configured

[Peer]
# r1.lan.buetow.org as r1.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 192.168.2.121/32
Endpoint = 192.168.1.121:56709
# No KeepAlive configured

[Peer]
# r2.lan.buetow.org as r2.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 192.168.2.122/32
Endpoint = 192.168.1.122:56709
# No KeepAlive configured

[Peer]
# blowfish.buetow.org as blowfish.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 192.168.2.110/32
Endpoint = 23.88.35.144:56709
PersistentKeepalive = 25

[Peer]
# fishfinger.buetow.org as fishfinger.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 192.168.2.111/32
Endpoint = 46.23.94.99:56709
PersistentKeepalive = 25

For roaming clients like pixel7pro (Android phone) or earth (Fedora laptop), the configuration looks different because they route all traffic through the VPN and only connect to the internet gateways:

[Interface]
# pixel7pro.wg0.wan.buetow.org
Address = 192.168.2.201
PrivateKey = **************************
ListenPort = 56709
DNS = 1.1.1.1, 8.8.8.8

[Peer]
# blowfish.buetow.org as blowfish.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 0.0.0.0/0, ::/0
Endpoint = 23.88.35.144:56709
PersistentKeepalive = 25

[Peer]
# fishfinger.buetow.org as fishfinger.wg0.wan.buetow.org
PublicKey = **************************
PresharedKey = **************************
AllowedIPs = 0.0.0.0/0, ::/0
Endpoint = 46.23.94.99:56709
PersistentKeepalive = 25

Note the key differences for roaming clients:

DNS is configured to use external DNS servers (Cloudflare and Google)
AllowedIPs = 0.0.0.0/0, ::/0 routes all traffic (IPv4 and IPv6) through the VPN
Only two peers are configured (the internet gateways), not the full mesh
PersistentKeepalive = 25 is used for both peers to maintain NAT traversal

Whereas there are two main sections. One is [Interface], which configures the current host (here: f0 or pixel7pro):

Address: Local virtual IP address on the WireGuard interface.
PrivateKey: Private key for this node.
ListenPort: Port on which this WireGuard interface listens for incoming connections.

And in the following, there is one [Peer] section for every peer node on the mesh network:

PublicKey: The public key of the remote peer is used to authenticate their identity.
PresharedKey: An optional extra symmetric key on top of the PublicKey.
AllowedIPs: IPs or subnets routed through this peer (traffic is allowed to/from these IPs).
Endpoint: The public IP:port combination of the remote peer for connection.
PersistentKeepalive: Keeps the tunnel alive by sending periodic packets; used for NAT traversal.

NAT traversal and keepalive

As all participating hosts, except for blowfish and fishfinger (which are on the internet), are behind a NAT gateway (my home router), we need to use PersistentKeepalive to establish and maintain the VPN tunnel from the LAN to the internet because:

By default, WireGuard tries to be as silent as possible when not being used; it is not a chatty protocol. For the most part, it only transmits data when a peer wishes to send packets. When it's not being asked to send packets, it stops sending packets until it is asked again. In the majority of configurations, this works well. However, when a peer is behind NAT or a firewall, it might wish to be able to receive incoming packets even when it is not sending any packets. Because NAT and stateful firewalls keep track of "connections", if a peer behind NAT or a firewall wishes to receive incoming packets, he must keep the NAT/firewall mapping valid, by periodically sending keepalive packets. This is called persistent keepalives. When this option is enabled, a keepalive packet is sent to the server endpoint once every interval seconds. A sensible interval that works with a wide variety of firewalls is 25 seconds. Setting it to 0 turns the feature off, which is the default, since most users will not need this, and it makes WireGuard slightly more chatty. This feature may be specified by adding the PersistentKeepalive = field to a peer in the configuration file, or setting persistent-keepalive at the command line. If you don't need this feature, don't enable it. But if you're behind NAT or a firewall and you want to receive incoming connections long after network traffic has gone silent, this option will keep the "connection" open in the eyes of NAT.

That's why you see PersistentKeepAlive = 25 in the blowfish and fishfinger peer configurations. This means that every 25 seconds, a keep-alive signal is sent over the tunnel to maintain its connection. If the tunnel is not yet established, it will be created within 25 seconds latest.

Without this, we might never have a VPN tunnel open, as the systems in the LAN may not actively attempt to contact blowfish and fishfinger on their own. In fact, the opposite would likely occur, with the traffic flowing inward instead of outward (this is beyond the scope of this blog post but will be covered in a later post in this series!).

Preshared key

The PSK (preshared key) is an optional extra symmetric key on top of the public key crypto. Both peers know it, so an attacker would need both the private keys and the PSK to decrypt anything. It's also a hedge against future weaknesses in the key exchange.

So, because it's better, we are using it.

Mesh network generator

Writing the wg0.conf for every peer by hand is cumbersome. Every peer needs its own key pair, every tunnel needs a preshared key (29 of them for 8 hosts), and both ends need matching AllowedIPs, Endpoint and PersistentKeepalive entries. That gets out of hand quickly, so I automated it.

I have written a Ruby script wireguardmeshgenerator.rb to do this for our purposes:

https://github.com/snonux/wireguardmeshgenerator

I use Fedora Linux as my main driver on my personal Laptop, so the script was developed and tested only on Fedora Linux. However, it should also work on other Linux and Unix-like systems.

To set up the mesh generator on Fedora Linux, we run the following:

> git clone https://github.com/snonux/wireguardmeshgenerator
> cd ./wireguardmeshgenerator
> bundle install
> sudo dnf install -y wireguard-tools

This assumes that Ruby and the bundler gem are already installed. If not, refer to the docs of your distribution.

wireguardmeshgenerator.yaml

The file wireguardmeshgenerator.yaml configures the mesh generator script.

---
hosts:
  f0:
    os: FreeBSD
    ssh:
      user: paul
      conf_dir: /usr/local/etc/wireguard
      sudo_cmd: doas
      reload_cmd: service wireguard reload
    lan:
      domain: 'lan.buetow.org'
      ip: '192.168.1.130'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.130'
      ipv6: 'fd42:beef:cafe:2::130'
    exclude_peers:
      - earth
      - pixel7pro
  f1:
    os: FreeBSD
    ssh:
      user: paul
      conf_dir: /usr/local/etc/wireguard
      sudo_cmd: doas
      reload_cmd: service wireguard reload
    lan:
      domain: 'lan.buetow.org'
      ip: '192.168.1.131'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.131'
      ipv6: 'fd42:beef:cafe:2::131'
    exclude_peers:
      - earth
      - pixel7pro
  f2:
    os: FreeBSD
    ssh:
      user: paul
      conf_dir: /usr/local/etc/wireguard
      sudo_cmd: doas
      reload_cmd: service wireguard reload
    lan:
      domain: 'lan.buetow.org'
      ip: '192.168.1.132'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.132'
      ipv6: 'fd42:beef:cafe:2::132'
    exclude_peers:
      - earth
      - pixel7pro
  r0:
    os: Linux
    ssh:
      user: root
      conf_dir: /etc/wireguard
      sudo_cmd:
      reload_cmd: systemctl reload wg-quick@wg0.service
    lan:
      domain: 'lan.buetow.org'
      ip: '192.168.1.120'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.120'
      ipv6: 'fd42:beef:cafe:2::120'
    exclude_peers:
      - earth
      - pixel7pro
  r1:
    os: Linux
    ssh:
      user: root
      conf_dir: /etc/wireguard
      sudo_cmd:
      reload_cmd: systemctl reload wg-quick@wg0.service
    lan:
      domain: 'lan.buetow.org'
      ip: '192.168.1.121'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.121'
      ipv6: 'fd42:beef:cafe:2::121'
    exclude_peers:
      - earth
      - pixel7pro
  r2:
    os: Linux
    ssh:
      user: root
      conf_dir: /etc/wireguard
      sudo_cmd:
      reload_cmd: systemctl reload wg-quick@wg0.service
    lan:
      domain: 'lan.buetow.org'
      ip: '192.168.1.122'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.122'
      ipv6: 'fd42:beef:cafe:2::122'
    exclude_peers:
      - earth
      - pixel7pro
  blowfish:
    os: OpenBSD
    ssh:
      user: rex
      port: 2
      conf_dir: /etc/wireguard
      sudo_cmd: doas
      reload_cmd: sh /etc/netstart wg0
    internet:
      domain: 'buetow.org'
      ip: '23.88.35.144'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.110'
      ipv6: 'fd42:beef:cafe:2::110'
    exclude_peers:
      - earth
      - pixel7pro
  fishfinger:
    os: OpenBSD
    ssh:
      user: rex
      port: 2
      conf_dir: /etc/wireguard
      sudo_cmd: doas
      reload_cmd: sh /etc/netstart wg0
    internet:
      domain: 'buetow.org'
      ip: '46.23.94.99'
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.111'
      ipv6: 'fd42:beef:cafe:2::111'
    exclude_peers:
      - earth
      - pixel7pro
  earth:
    os: Linux
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.200'
      ipv6: 'fd42:beef:cafe:2::200'
    exclude_peers:
      - f0
      - f1
      - f2
      - r0
      - r1
      - r2
      - pixel7pro
  pixel7pro:
    os: Android
    wg0:
      domain: 'wg0.wan.buetow.org'
      ip: '192.168.2.201'
      ipv6: 'fd42:beef:cafe:2::201'
    exclude_peers:
      - f0
      - f1
      - f2
      - r0
      - r1
      - r2
      - earth

Per host, the file holds the SSH details (user, config dir, sudo and reload commands) and the IPs and domains of the LAN (or internet) interface and the wg0 interface. Hosts with an internet section are the publicly reachable ones.

The earth and pixel7pro entries look different: they have no lan or internet section, which tells the generator that they are roaming clients. exclude_peers limits them to the two internet gateways (blowfish and fishfinger), so the LAN hosts can't reach them. The generator gives them AllowedIPs = 0.0.0.0/0, ::/0 (route everything through the VPN), DNS servers (1.1.1.1, 8.8.8.8), and PersistentKeepalive for NAT traversal.

wireguardmeshgenerator.rb overview

The wireguardmeshgenerator.rb script consists of the following base classes:

KeyTool: Manages WireGuard key generation and retrieval. If a key pair or a PSK is missing, it generates it with the wg tool. It provides methods to read the public/private keys and retrieve or generate a PSK for communication with a peer. The keys are stored in a temp directory on the system from where the generator is run.
PeerSnippet: A Struct representing the configuration for a single WireGuard peer in the mesh. Based on the provided attributes and configuration, it generates the peer's WireGuard configuration, including public key, PSK, allowed IPs, endpoint, and keepalive settings.
WireguardConfig: This function generates WireGuard configuration files for the specified host in the mesh network. It includes the [Interface] section for the host itself and the [Peer] sections for all other peers. It can also clean up generated files and directories and create the required directory structure for storing configuration files locally on the system from which the script is run.
InstallConfig: Uploads the config file to the remote host via SCP, creates the directories if needed, moves the file into place, and reloads the WireGuard service via SSH.

At the end (if you want to see the code for the stuff listed above, go to the Git repo and have a look), we glue it all together in this block:

begin
  options = { hosts: [] }
  OptionParser.new do |opts|
    opts.banner = 'Usage: wireguardmeshgenerator.rb [options]'
    opts.on('--generate', 'Generate Wireguard configs') do
      options[:generate] = true
    end
    opts.on('--install', 'Install Wireguard configs') do
      options[:install] = true
    end
    opts.on('--clean', 'Clean Wireguard configs') do
      options[:clean] = true
    end
    opts.on('--hosts=HOSTS', 'Comma separated hosts to configure') do |hosts|
      options[:hosts] = hosts.split(',')
    end
  end.parse!

  conf = YAML.load_file('wireguardmeshgenerator.yaml').freeze
  conf['hosts'].keys.select { options[:hosts].empty? || options[:hosts].include?(_1) }
               .each do |host|
    # Generate Wireguard configuration for the host reload!
    WireguardConfig.new(host, conf['hosts']).generate! if options[:generate]
    # Install Wireguard configuration for the host.
    InstallConfig.new(host, conf['hosts']).upload!.install!.reload! if options[:install]
    # Clean Wireguard configuration for the host.
    WireguardConfig.new(host, conf['hosts']).clean! if options[:clean]
  end
rescue StandardError => e
  puts "Error: #{e.message}"
  puts e.backtrace.join("\n")
  exit 2
end

And we also have a Rakefile:

task :generate do
  ruby 'wireguardmeshgenerator.rb', '--generate'
end

task :clean do
  ruby 'wireguardmeshgenerator.rb', '--clean'
end

task :install do
  ruby 'wireguardmeshgenerator.rb', '--install'
end

task default: :generate

Invoking the mesh network generator

Generating the wg0.conf files and keys

To generate everything (the wg0.conf of all participating hosts, including all keys involved), we run the following:

> rake generate
/usr/bin/ruby wireguardmeshgenerator.rb --generate
Generating dist/f0/etc/wireguard/wg0.conf
Generating dist/f1/etc/wireguard/wg0.conf
Generating dist/f2/etc/wireguard/wg0.conf
Generating dist/r0/etc/wireguard/wg0.conf
Generating dist/r1/etc/wireguard/wg0.conf
Generating dist/r2/etc/wireguard/wg0.conf
Generating dist/blowfish/etc/wireguard/wg0.conf
Generating dist/fishfinger/etc/wireguard/wg0.conf
Generating dist/earth/etc/wireguard/wg0.conf
Generating dist/pixel7pro/etc/wireguard/wg0.conf

It generated all the wg0.conf files listed in the output, plus those keys:

> find keys/ -type f
keys/f0/priv.key
keys/f0/pub.key
keys/psk/f0_f1.key
keys/psk/f0_f2.key
keys/psk/f0_r0.key
keys/psk/f0_r1.key
keys/psk/f0_r2.key
keys/psk/blowfish_f0.key
keys/psk/f0_fishfinger.key
keys/psk/f1_f2.key
keys/psk/f1_r0.key
keys/psk/f1_r1.key
keys/psk/f1_r2.key
keys/psk/blowfish_f1.key
keys/psk/f1_fishfinger.key
keys/psk/f2_r0.key
keys/psk/f2_r1.key
keys/psk/f2_r2.key
keys/psk/blowfish_f2.key
keys/psk/f2_fishfinger.key
keys/psk/r0_r1.key
keys/psk/r0_r2.key
keys/psk/blowfish_r0.key
keys/psk/fishfinger_r0.key
keys/psk/r1_r2.key
keys/psk/blowfish_r1.key
keys/psk/fishfinger_r1.key
keys/psk/blowfish_r2.key
keys/psk/fishfinger_r2.key
keys/psk/blowfish_fishfinger.key
keys/psk/blowfish_earth.key
keys/psk/earth_fishfinger.key
keys/psk/blowfish_pixel7pro.key
keys/psk/fishfinger_pixel7pro.key
keys/f1/priv.key
keys/f1/pub.key
keys/f2/priv.key
keys/f2/pub.key
keys/r0/priv.key
keys/r0/pub.key
keys/r1/priv.key
keys/r1/pub.key
keys/r2/priv.key
keys/r2/pub.key
keys/blowfish/priv.key
keys/blowfish/pub.key
keys/fishfinger/priv.key
keys/fishfinger/pub.key
keys/earth/priv.key
keys/earth/pub.key
keys/pixel7pro/priv.key
keys/pixel7pro/pub.key

Those keys are embedded in the resulting wg0.conf, so later, we only need to install the wg0.conf files and not all the keys individually.

Installing the wg0.conf files

Uploading the wg0.conf files to the participating hosts and reloading WireGuard on them is then just a matter of executing (this expects, that all participating hosts are up and running):

> rake install
/usr/bin/ruby wireguardmeshgenerator.rb --install
Uploading dist/f0/etc/wireguard/wg0.conf to f0.lan.buetow.org:.
Installing Wireguard config on f0
Uploading cmd.sh to f0.lan.buetow.org:.
+ [ ! -d /usr/local/etc/wireguard ]
+ doas chmod 700 /usr/local/etc/wireguard
+ doas mv -v wg0.conf /usr/local/etc/wireguard
wg0.conf -> /usr/local/etc/wireguard/wg0.conf
+ doas chmod 644 /usr/local/etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on f0
Uploading cmd.sh to f0.lan.buetow.org:.
+ doas service wireguard reload
+ rm cmd.sh
Uploading dist/f1/etc/wireguard/wg0.conf to f1.lan.buetow.org:.
Installing Wireguard config on f1
Uploading cmd.sh to f1.lan.buetow.org:.
+ [ ! -d /usr/local/etc/wireguard ]
+ doas chmod 700 /usr/local/etc/wireguard
+ doas mv -v wg0.conf /usr/local/etc/wireguard
wg0.conf -> /usr/local/etc/wireguard/wg0.conf
+ doas chmod 644 /usr/local/etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on f1
Uploading cmd.sh to f1.lan.buetow.org:.
+ doas service wireguard reload
+ rm cmd.sh
Uploading dist/f2/etc/wireguard/wg0.conf to f2.lan.buetow.org:.
Installing Wireguard config on f2
Uploading cmd.sh to f2.lan.buetow.org:.
+ [ ! -d /usr/local/etc/wireguard ]
+ doas chmod 700 /usr/local/etc/wireguard
+ doas mv -v wg0.conf /usr/local/etc/wireguard
wg0.conf -> /usr/local/etc/wireguard/wg0.conf
+ doas chmod 644 /usr/local/etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on f2
Uploading cmd.sh to f2.lan.buetow.org:.
+ doas service wireguard reload
+ rm cmd.sh
Uploading dist/r0/etc/wireguard/wg0.conf to r0.lan.buetow.org:.
Installing Wireguard config on r0
Uploading cmd.sh to r0.lan.buetow.org:.
+ '[' '!' -d /etc/wireguard ']'
+ chmod 700 /etc/wireguard
+ mv -v wg0.conf /etc/wireguard
renamed 'wg0.conf' -> '/etc/wireguard/wg0.conf'
+ chmod 644 /etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on r0
Uploading cmd.sh to r0.lan.buetow.org:.
+ systemctl reload wg-quick@wg0.service
+ rm cmd.sh
Uploading dist/r1/etc/wireguard/wg0.conf to r1.lan.buetow.org:.
Installing Wireguard config on r1
Uploading cmd.sh to r1.lan.buetow.org:.
+ '[' '!' -d /etc/wireguard ']'
+ chmod 700 /etc/wireguard
+ mv -v wg0.conf /etc/wireguard
renamed 'wg0.conf' -> '/etc/wireguard/wg0.conf'
+ chmod 644 /etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on r1
Uploading cmd.sh to r1.lan.buetow.org:.
+ systemctl reload wg-quick@wg0.service
+ rm cmd.sh
Uploading dist/r2/etc/wireguard/wg0.conf to r2.lan.buetow.org:.
Installing Wireguard config on r2
Uploading cmd.sh to r2.lan.buetow.org:.
+ '[' '!' -d /etc/wireguard ']'
+ chmod 700 /etc/wireguard
+ mv -v wg0.conf /etc/wireguard
renamed 'wg0.conf' -> '/etc/wireguard/wg0.conf'
+ chmod 644 /etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on r2
Uploading cmd.sh to r2.lan.buetow.org:.
+ systemctl reload wg-quick@wg0.service
+ rm cmd.sh
Uploading dist/blowfish/etc/wireguard/wg0.conf to blowfish.buetow.org:.
Installing Wireguard config on blowfish
Uploading cmd.sh to blowfish.buetow.org:.
+ [ ! -d /etc/wireguard ]
+ doas chmod 700 /etc/wireguard
+ doas mv -v wg0.conf /etc/wireguard
wg0.conf -> /etc/wireguard/wg0.conf
+ doas chmod 644 /etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on blowfish
Uploading cmd.sh to blowfish.buetow.org:.
+ doas sh /etc/netstart wg0
+ rm cmd.sh
Uploading dist/fishfinger/etc/wireguard/wg0.conf to fishfinger.buetow.org:.
Installing Wireguard config on fishfinger
Uploading cmd.sh to fishfinger.buetow.org:.
+ [ ! -d /etc/wireguard ]
+ doas chmod 700 /etc/wireguard
+ doas mv -v wg0.conf /etc/wireguard
wg0.conf -> /etc/wireguard/wg0.conf
+ doas chmod 644 /etc/wireguard/wg0.conf
+ rm cmd.sh
Reloading Wireguard on fishfinger
Uploading cmd.sh to fishfinger.buetow.org:.
+ doas sh /etc/netstart wg0
+ rm cmd.sh

Re-generating mesh and installing the wg0.conf files again

The mesh network can be re-generated and re-installed as follows:

> rake clean
> rake generate
> rake install

That would also delete and re-generate all the keys involved.

Setting up roaming clients

For roaming clients like earth (Fedora laptop) and pixel7pro (Android phone), the setup process differs slightly since these devices are not always accessible via SSH:

Android phone (pixel7pro):

The configuration is transferred to the phone using a QR code. The official WireGuard Android app (from Google Play Store) can scan and import the configuration:

> sudo dnf install qrencode
> qrencode -t ansiutf8 < dist/pixel7pro/etc/wireguard/wg0.conf

Scan the QR code with the WireGuard app to import the configuration. The phone will then route all traffic through the VPN when the tunnel is activated. Note that WireGuard does not support automatic failover between the two gateways (blowfish and fishfinger)—if one fails, manual disconnection and reconnection is required to switch to the other.

Fedora laptop (earth):

For the laptop, manually copy the generated configuration:

> sudo cp dist/earth/etc/wireguard/wg0.conf /etc/wireguard/
> sudo chmod 600 /etc/wireguard/wg0.conf
> sudo systemctl start wg-quick@wg0.service  # Start manually
> sudo systemctl disable wg-quick@wg0.service  # Prevent auto-start

The service stays disabled, so the VPN is only up when I start it by hand.

Adding IPv6 support to the mesh

After the IPv4-only mesh was running, I added IPv6 as well (dual-stack). Mostly to learn, and to be ready when I need it. All 10 hosts (8 infrastructure + 2 roaming clients) now have both IPv4 and IPv6 addresses on their WireGuard interfaces.

IPv6 addressing scheme

We use ULA (Unique Local Address) private IPv6 space, analogous to RFC1918 private IPv4 addresses:

Prefix: fd42:beef:cafe::/48
Subnet: fd42:beef:cafe:2::/64 (wg0 interfaces)

All hosts receive dual-stack addresses:

fd42:beef:cafe:2::110/64  - blowfish.wg0 (OpenBSD gateway)
fd42:beef:cafe:2::111/64  - fishfinger.wg0 (OpenBSD gateway)
fd42:beef:cafe:2::120/64  - r0.wg0 (Rocky Linux VM)
fd42:beef:cafe:2::121/64  - r1.wg0 (Rocky Linux VM)
fd42:beef:cafe:2::122/64  - r2.wg0 (Rocky Linux VM)
fd42:beef:cafe:2::130/64  - f0.wg0 (FreeBSD host)
fd42:beef:cafe:2::131/64  - f1.wg0 (FreeBSD host)
fd42:beef:cafe:2::132/64  - f2.wg0 (FreeBSD host)
fd42:beef:cafe:2::200/64  - earth.wg0 (roaming laptop)
fd42:beef:cafe:2::201/64  - pixel7pro.wg0 (roaming phone)

Updating the mesh generator for IPv6

The mesh generator required two modifications to support dual-stack configurations:

1. Address generation (address method):

The generator now outputs multiple Address directives when IPv6 is present:

def address
  return '# No Address = ... for OpenBSD here' if hosts[myself]['os'] == 'OpenBSD'

  ipv4 = hosts[myself]['wg0']['ip']
  ipv6 = hosts[myself]['wg0']['ipv6']

  # WireGuard supports multiple Address directives for dual-stack
  if ipv6
    "Address = #{ipv4}\nAddress = #{ipv6}/64"
  else
    "Address = #{ipv4}"
  end
end

2. AllowedIPs generation (peers method):

For mesh peers, both IPv4 and IPv6 addresses are included in AllowedIPs:

if is_roaming
  allowed_ips = '0.0.0.0/0, ::/0'
else
  # For mesh peers, allow both IPv4 and IPv6 if present
  ipv4 = data['wg0']['ip']
  ipv6 = data['wg0']['ipv6']
  allowed_ips = ipv6 ? "#{ipv4}/32, #{ipv6}/128" : "#{ipv4}/32"
end

Roaming clients keep AllowedIPs = 0.0.0.0/0, ::/0 to route all traffic (IPv4 and IPv6) through the VPN.

IPv6 NAT on OpenBSD gateways

To allow roaming clients to access the internet via IPv6, we added NAT66 rules to the OpenBSD gateways' pf.conf:

# NAT for WireGuard clients to access internet (IPv4)
match out on vio0 from 192.168.2.0/24 to any nat-to (vio0)

# NAT66 for WireGuard clients to access internet (IPv6)
# Uses NPTv6 (Network Prefix Translation) to translate ULA to public IPv6
match out on vio0 inet6 from fd42:beef:cafe:2::/64 to any nat-to (vio0)

# Allow all UDP traffic on WireGuard port (IPv4 and IPv6)
pass in inet proto udp from any to any port 56709
pass in inet6 proto udp from any to any port 56709

OpenBSD's PF firewall supports IPv6 NAT with the same syntax as IPv4, using NPTv6 (RFC 6296) to translate the ULA addresses to the gateway's public IPv6 address.

Manual OpenBSD interface configuration

Since OpenBSD doesn't use the Address directive in WireGuard configs, IPv6 must be manually configured on the wg0 interfaces. On blowfish:

rex@blowfish:~ $ doas vi /etc/hostname.wg0

Add the IPv6 address (note the order - IPv6 must be configured before up):

inet 192.168.2.110 255.255.255.0 NONE
inet6 fd42:beef:cafe:2::110 64
up
!/usr/local/bin/wg setconf wg0 /etc/wireguard/wg0.conf

Apply the configuration:

rex@blowfish:~ $ doas sh /etc/netstart wg0
rex@blowfish:~ $ ifconfig wg0 | grep inet6
inet6 fd42:beef:cafe:2::110 prefixlen 64

Repeat for fishfinger with address fd42:beef:cafe:2::111.

After reboot, the interface will automatically come up with both IPv4 and IPv6 addresses. WireGuard peers may take 30-60 seconds to establish handshakes after boot.

Verifying dual-stack connectivity

After regenerating and deploying the configurations, both IPv4 and IPv6 work across the mesh:

# From r0 (Rocky Linux VM)
root@r0:~ # ping -c 2 192.168.2.130  # IPv4 to f0
64 bytes from 192.168.2.130: icmp_seq=1 ttl=64 time=2.12 ms
64 bytes from 192.168.2.130: icmp_seq=2 ttl=64 time=0.681 ms

root@r0:~ # ping6 -c 2 fd42:beef:cafe:2::130  # IPv6 to f0
64 bytes from fd42:beef:cafe:2::130: icmp_seq=1 ttl=64 time=2.16 ms
64 bytes from fd42:beef:cafe:2::130: icmp_seq=2 ttl=64 time=0.909 ms

Hosts without an ipv6 field in the YAML still get IPv4-only configs.

Happy WireGuard-ing

All is set up now. E.g. on f0:

paul@f0:~ % doas wg show
interface: wg0
  public key: Jm6YItMt94++dIeOyVi1I9AhNt2qQcryxCZezoX7X2Y=
  private key: (hidden)
  listening port: 56709

peer: 8PvGZH1NohHpZPVJyjhctBX9xblsNvYBhpg68FsFcns=
  preshared key: (hidden)
  endpoint: 46.23.94.99:56709
  allowed ips: 192.168.2.111/32, fd42:beef:cafe:2::111/128
  latest handshake: 1 minute, 46 seconds ago
  transfer: 124 B received, 1.75 KiB sent
  persistent keepalive: every 25 seconds

peer: Xow+d3qVXgUMk4pcRSQ6Fe+vhYBa3VDyHX/4jrGoKns=
  preshared key: (hidden)
  endpoint: 23.88.35.144:56709
  allowed ips: 192.168.2.110/32, fd42:beef:cafe:2::110/128
  latest handshake: 1 minute, 52 seconds ago
  transfer: 124 B received, 1.60 KiB sent
  persistent keepalive: every 25 seconds

peer: s3e93XoY7dPUQgLiVO4d8x/SRCFgEew+/wP7+zwgehI=
  preshared key: (hidden)
  endpoint: 192.168.1.120:56709
  allowed ips: 192.168.2.120/32, fd42:beef:cafe:2::120/128

peer: 2htXdNcxzpI2FdPDJy4T4VGtm1wpMEQu1AkQHjNY6F8=
  preshared key: (hidden)
  endpoint: 192.168.1.131:56709
  allowed ips: 192.168.2.131/32, fd42:beef:cafe:2::131/128

peer: 0Y/H20W8YIbF7DA1sMwMacLI8WS9yG+1/QO7m2oyllg=
  preshared key: (hidden)
  endpoint: 192.168.1.122:56709
  allowed ips: 192.168.2.122/32, fd42:beef:cafe:2::122/128

peer: Hhy9kMPOOjChXV2RA5WeCGs+J0FE3rcNPDw/TLSn7i8=
  preshared key: (hidden)
  endpoint: 192.168.1.121:56709
  allowed ips: 192.168.2.121/32, fd42:beef:cafe:2::121/128

peer: SlGVsACE1wiaRoGvCR3f7AuHfRS+1jjhS+YwEJ2HvF0=
  preshared key: (hidden)
  endpoint: 192.168.1.132:56709
  allowed ips: 192.168.2.132/32, fd42:beef:cafe:2::132/128

All the hosts are pingable as well, e.g.:

paul@f0:~ % foreach peer ( f1 f2 r0 r1 r2 blowfish fishfinger )
foreach? ping -c2 $peer.wg0
foreach? echo
foreach? end
PING f1.wg0 (192.168.2.131): 56 data bytes
64 bytes from 192.168.2.131: icmp_seq=0 ttl=64 time=0.334 ms
64 bytes from 192.168.2.131: icmp_seq=1 ttl=64 time=0.260 ms

--- f1.wg0 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.260/0.297/0.334/0.037 ms

PING f2.wg0 (192.168.2.132): 56 data bytes
64 bytes from 192.168.2.132: icmp_seq=0 ttl=64 time=0.323 ms
64 bytes from 192.168.2.132: icmp_seq=1 ttl=64 time=0.303 ms

--- f2.wg0 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.303/0.313/0.323/0.010 ms

PING r0.wg0 (192.168.2.120): 56 data bytes
64 bytes from 192.168.2.120: icmp_seq=0 ttl=64 time=0.716 ms
64 bytes from 192.168.2.120: icmp_seq=1 ttl=64 time=0.406 ms

--- r0.wg0 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.406/0.561/0.716/0.155 ms

PING r1.wg0 (192.168.2.121): 56 data bytes
64 bytes from 192.168.2.121: icmp_seq=0 ttl=64 time=0.639 ms
64 bytes from 192.168.2.121: icmp_seq=1 ttl=64 time=0.629 ms

--- r1.wg0 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.629/0.634/0.639/0.005 ms

PING r2.wg0 (192.168.2.122): 56 data bytes
64 bytes from 192.168.2.122: icmp_seq=0 ttl=64 time=0.569 ms
64 bytes from 192.168.2.122: icmp_seq=1 ttl=64 time=0.479 ms

--- r2.wg0 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.479/0.524/0.569/0.045 ms

PING blowfish.wg0 (192.168.2.110): 56 data bytes
64 bytes from 192.168.2.110: icmp_seq=0 ttl=255 time=35.745 ms
64 bytes from 192.168.2.110: icmp_seq=1 ttl=255 time=35.481 ms

--- blowfish.wg0 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 35.481/35.613/35.745/0.132 ms

PING fishfinger.wg0 (192.168.2.111): 56 data bytes
64 bytes from 192.168.2.111: icmp_seq=0 ttl=255 time=33.992 ms
64 bytes from 192.168.2.111: icmp_seq=1 ttl=255 time=33.751 ms

--- fishfinger.wg0 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 33.751/33.872/33.992/0.120 ms

Note that the loop above is a tcsh loop, the default shell used in FreeBSD. Of course, all other peers can ping their peers as well!

After the first ping, VPN tunnels now also show handshakes and the amount of data transferred through them:

paul@f0:~ % doas wg show
interface: wg0
  public key: Jm6YItMt94++dIeOyVi1I9AhNt2qQcryxCZezoX7X2Y=
  private key: (hidden)
  listening port: 56709

peer: 0Y/H20W8YIbF7DA1sMwMacLI8WS9yG+1/QO7m2oyllg=
  preshared key: (hidden)
  endpoint: 192.168.1.122:56709
  allowed ips: 192.168.2.122/32, fd42:beef:cafe:2::122/128
  latest handshake: 10 seconds ago
  transfer: 440 B received, 532 B sent

peer: Hhy9kMPOOjChXV2RA5WeCGs+J0FE3rcNPDw/TLSn7i8=
  preshared key: (hidden)
  endpoint: 192.168.1.121:56709
  allowed ips: 192.168.2.121/32, fd42:beef:cafe:2::121/128
  latest handshake: 12 seconds ago
  transfer: 440 B received, 564 B sent

peer: s3e93XoY7dPUQgLiVO4d8x/SRCFgEew+/wP7+zwgehI=
  preshared key: (hidden)
  endpoint: 192.168.1.120:56709
  allowed ips: 192.168.2.120/32, fd42:beef:cafe:2::120/128
  latest handshake: 14 seconds ago
  transfer: 440 B received, 564 B sent

peer: SlGVsACE1wiaRoGvCR3f7AuHfRS+1jjhS+YwEJ2HvF0=
  preshared key: (hidden)
  endpoint: 192.168.1.132:56709
  allowed ips: 192.168.2.132/32, fd42:beef:cafe:2::132/128
  latest handshake: 17 seconds ago
  transfer: 472 B received, 564 B sent

peer: Xow+d3qVXgUMk4pcRSQ6Fe+vhYBa3VDyHX/4jrGoKns=
  preshared key: (hidden)
  endpoint: 23.88.35.144:56709
  allowed ips: 192.168.2.110/32, fd42:beef:cafe:2::110/128
  latest handshake: 55 seconds ago
  transfer: 472 B received, 596 B sent
  persistent keepalive: every 25 seconds

peer: 8PvGZH1NohHpZPVJyjhctBX9xblsNvYBhpg68FsFcns=
  preshared key: (hidden)
  endpoint: 46.23.94.99:56709
  allowed ips: 192.168.2.111/32, fd42:beef:cafe:2::111/128
  latest handshake: 55 seconds ago
  transfer: 472 B received, 596 B sent
  persistent keepalive: every 25 seconds

peer: 2htXdNcxzpI2FdPDJy4T4VGtm1wpMEQu1AkQHjNY6F8=
  preshared key: (hidden)
  endpoint: 192.168.1.131:56709
  allowed ips: 192.168.2.131/32, fd42:beef:cafe:2::131/128

Managing Roaming Client Tunnels

Since roaming clients like earth and pixel7pro connect on-demand rather than being always-on like the infrastructure hosts, it's useful to know how to configure and manage the WireGuard tunnels.

Manual gateway failover configuration

The default configuration for roaming clients includes both gateways (blowfish and fishfinger) with AllowedIPs = 0.0.0.0/0, ::/0. However, WireGuard doesn't automatically failover between multiple peers with identical AllowedIPs routes. When both gateways are configured this way, WireGuard uses the first peer with a recent handshake. If that gateway goes down, traffic won't automatically switch to the backup gateway.

So for manual failover, I generate two config files per roaming client, each with only one gateway peer. Then I pick the gateway by picking the config.

Configuration files for pixel7pro (phone):

Two separate configs in /home/paul/git/wireguardmeshgenerator/dist/pixel7pro/etc/wireguard/:

wg0-blowfish.conf - Routes all traffic through blowfish gateway (23.88.35.144)
wg0-fishfinger.conf - Routes all traffic through fishfinger gateway (46.23.94.99)

Generate QR codes for importing into the WireGuard Android app:

qrencode -t ansiutf8 < dist/pixel7pro/etc/wireguard/wg0-blowfish.conf
qrencode -t ansiutf8 < dist/pixel7pro/etc/wireguard/wg0-fishfinger.conf

Import both QR codes using the WireGuard app to create two separate tunnel profiles. You can then manually enable/disable each tunnel to select which gateway to use. Only enable one tunnel at a time.

Configuration files for earth (laptop):

Two separate configs in /home/paul/git/wireguardmeshgenerator/dist/earth/etc/wireguard/:

wg0-blowfish.conf - Routes all traffic through blowfish gateway
wg0-fishfinger.conf - Routes all traffic through fishfinger gateway

Install both configurations:

sudo cp dist/earth/etc/wireguard/wg0-blowfish.conf /etc/wireguard/
sudo cp dist/earth/etc/wireguard/wg0-fishfinger.conf /etc/wireguard/

Starting and stopping on earth (Fedora laptop)

On the Fedora laptop, WireGuard is managed via systemd. Using the separate gateway configs:

# Start with blowfish gateway
earth$ sudo systemctl start wg-quick@wg0-blowfish.service

# Or start with fishfinger gateway
earth$ sudo systemctl start wg-quick@wg0-fishfinger.service

# Check tunnel status (example with blowfish gateway)
earth$ sudo wg show
interface: wg0
  public key: Mc1CpSS3rbLN9A2w9c75XugQyXUkGPHKI2iCGbh8DRo=
  private key: (hidden)
  listening port: 56709
  fwmark: 0xca6c

peer: Xow+d3qVXgUMk4pcRSQ6Fe+vhYBa3VDyHX/4jrGoKns=
  preshared key: (hidden)
  endpoint: 23.88.35.144:56709
  allowed ips: 0.0.0.0/0, ::/0
  latest handshake: 5 seconds ago
  transfer: 15.89 KiB received, 32.15 KiB sent
  persistent keepalive: every 25 seconds

Stopping the tunnel:

earth$ sudo systemctl stop wg-quick@wg0-blowfish.service
# Or if using fishfinger:
earth$ sudo systemctl stop wg-quick@wg0-fishfinger.service

earth$ sudo wg show
# No output - WireGuard interface is down

Switching between gateways:

# Switch from blowfish to fishfinger
earth$ sudo systemctl stop wg-quick@wg0-blowfish.service
earth$ sudo systemctl start wg-quick@wg0-fishfinger.service

Starting and stopping on pixel7pro (Android phone)

On Android using the official WireGuard app, you now have two tunnel profiles (wg0-blowfish and wg0-fishfinger) after importing the QR codes:

In the WireGuard app, tap the toggle next to wg0-blowfish or wg0-fishfinger to start that tunnel (a key icon shows up in the notification bar). Tap it again to stop. Only enable one at a time. The WireGuard notification in the shade also works as a quick toggle.

The WireGuard Android app supports automatically activating tunnels based on:

Mobile data connection (e.g., enable VPN when on cellular)
WiFi SSID (e.g., disable VPN when on trusted home network)
Ethernet connection status

These settings can be configured by tapping the pencil icon next to the tunnel name, then scrolling to "Toggle on/off based on" options.

Verifying connectivity

Once the tunnel is active on either device, verify connectivity:

# From earth laptop:
earth$ ping -c2 blowfish.wg0
earth$ ping -c2 fishfinger.wg0
earth$ curl https://ifconfig.me  # Should show gateway's public IP

Check which gateway is active: Check the transfer statistics with sudo wg show on earth to see which peer shows recent handshakes and increasing transfer bytes. On Android, the WireGuard app shows the active tunnel with data transfer statistics.

Conclusion