Installing and Using WireGuard VPN with NetworkManager on Arch Linux

WireGuard is a fast, modern VPN protocol designed for simplicity and high performance. On Arch Linux, it integrates smoothly using wg-quick, but things get tricky when NetworkManager and DNS resolution come into play.

This post shows you how to:

• Set up WireGuard using a prebuilt or custom config
• Fix the common DNS resolvconf error
• Integrate WireGuard with NetworkManager

✅ Install WireGuard

sudo pacman -S wireguard-tools

This installs:

• wg: CLI tool for key and interface management
• wg-quick: Script for quickly bringing interfaces up/down

⚡ Option A: I Have a Prebuilt Config File

If you received a ready-made .conf file from your VPN provider (like Mullvad, ProtonVPN, or a self-hosted server), follow these steps:

1. Copy the file into place:

sudo cp my-vpn.conf /etc/wireguard/wg0.conf
sudo chmod 600 /etc/wireguard/wg0.conf

You can name it anything (e.g., home.conf, server.conf), but wg0.conf is conventional.

2. Remove the DNS line (important!)

Open the config file:

sudo nano /etc/wireguard/wg0.conf

Comment out or delete the line:

# DNS = 1.1.1.1

Why? Because wg-quick will try to apply this using resolvconf, which conflicts with NetworkManager and systemd-resolved.

3. Start the VPN:

sudo wg-quick up wg0

⚙️ Option B: Manual Configuration

If you’re setting up WireGuard manually:

1. Generate Keys

umask 077
wg genkey | tee privatekey | wg pubkey > publickey

2. Create /etc/wireguard/wg0.conf

[Interface]
PrivateKey = <your-private-key>
Address = 10.0.0.2/24
# DNS = 1.1.1.1

[Peer]
PublicKey = <peer-public-key>
Endpoint = <server-ip>:51820
AllowedIPs = 0.0.0.0/0
PersistentKeepalive = 25

Again, comment or remove the DNS line if you’re using NetworkManager.

🚫 Common Error: resolvconf: signature mismatch

If you try to start the VPN and see this:

resolvconf: signature mismatch: /etc/resolv.conf

It means wg-quick is trying to use resolvconf, but your system’s DNS is managed by systemd-resolved, often through NetworkManager.

✅ The Fix: Let NetworkManager Handle DNS

1. Edit your config:

   • Remove or comment out the DNS = ... line.

2. Restart the VPN interface:

sudo wg-quick up wg0

No more DNS error!

🌐 Optional: Manually Set DNS (If Needed)

If you want to override DNS manually:

Using systemd-resolved:

sudo resolvectl dns wg0 1.1.1.1
sudo resolvectl domain wg0 ~.

Using NetworkManager:

nmcli connection modify wg0 ipv4.dns "1.1.1.1"
nmcli connection up wg0

🧪 Test Your Connection

ping 1.1.1.1
ping archlinux.org
curl ip.me
curl ifconfig.me

If the IP shown is your VPN server’s IP, you’re connected securely.

⏹️ Stopping the VPN

To disconnect and stop the WireGuard VPN interface:

sudo wg-quick down wg0

This will bring down the VPN tunnel and restore your previous network settings.

🔁 Autostart on Boot (Optional)

To automatically start the VPN at boot:

sudo systemctl enable wg-quick@wg0

✅ Summary

Task	Command or Tip
Install WireGuard	sudo pacman -S wireguard-tools
Use prebuilt config	Place in /etc/wireguard/wg0.conf
Avoid DNS errors	Remove DNS = ... if using NetworkManager
Start connection	sudo wg-quick up wg0
Set DNS manually	Use resolvectl or nmcli
Verify connection	curl ifconfig.me
Autostart on boot	sudo systemctl enable wg-quick@wg0

WireGuard and Arch Linux are a perfect match: fast, lightweight, and modular. Just make sure DNS responsibilities are clear — let WireGuard handle the tunnel, and let NetworkManager handle the DNS.