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WireGuard VPN Handshake Timeout — Peer Connection Failure and No Traffic

Errornetwork

Overview

Fix WireGuard VPN handshake timeouts where peers cannot establish a connection, showing no recent handshake or transfer in wg show output.

Key Details

  • WireGuard uses a cryptokey routing model where each peer has a public key and allowed IPs
  • A successful handshake should appear within seconds of initiating a connection
  • wg show displays handshake time and transfer stats — no handshake means the connection failed
  • WireGuard uses UDP (default port 51820) which must be allowed through all firewalls
  • Unlike OpenVPN, WireGuard does not negotiate — both sides must have matching configurations

Common Causes

  • Firewall blocking UDP port 51820 (or custom port) on the server or client side
  • Incorrect peer public key — even one character wrong prevents handshake
  • Endpoint address incorrect or DNS not resolving the server hostname
  • AllowedIPs configuration mismatch preventing traffic from being routed through the tunnel

Steps

  1. 1Check WireGuard status: 'sudo wg show' — look for 'latest handshake' and 'transfer' values
  2. 2Verify the server firewall allows UDP on the WireGuard port: ufw allow 51820/udp
  3. 3Confirm peer public keys match: the server's peer section must have the client's public key and vice versa
  4. 4Test UDP connectivity: 'nc -zuv server-ip 51820' to verify the port is reachable
  5. 5Check AllowedIPs: server should have client's tunnel IP, client should have 0.0.0.0/0 for full tunnel

Tags

wireguardvpnhandshaketimeouttunnel

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Frequently Asked Questions

Run 'sudo wg show'. A successful connection shows 'latest handshake: X seconds/minutes ago' and non-zero transfer values. No handshake or handshake older than 2 minutes indicates a connection problem.