Which port is commonly used by WireGuard for UDP-based VPN?

• A. 1194 UDP
• B. 443 UDP
• C. 51820 UDP
• D. 51820 TCP

Answer: (C)

WireGuard is built to run over UDP, and the standard default port it uses is 51820. This port choice keeps the protocol lightweight and low-latency, avoiding the overhead and retransmission behavior of TCP, which is why UDP is favored for VPN traffic. In many official docs and typical client configurations, you’ll see WireGuard set up to listen on UDP 51820 by default, making it the most common, out-of-the-box choice.

Why the other options aren’t the right fit here: 1194 UDP is known as the default port for OpenVPN, not WireGuard, so it’s associated with a different VPN protocol. 443 UDP is commonly used for HTTPS and can be repurposed in some setups to traverse firewalls, but it’s not the standard default for WireGuard. Finally, 51820 TCP isn’t correct because WireGuard operates over UDP; using TCP would change how the protocol handles ordering and reliability, which WireGuard deliberately avoids.

If you need to work around strict firewall rules, you can configure WireGuard to use a different UDP port, including ports that are more likely to be open, but 51820 UDP remains the common default.