diff --git a/src/config.js b/src/config.js
index 3281523f..4e0c7a7b 100644
--- a/src/config.js
+++ b/src/config.js
@@ -10,7 +10,7 @@ module.exports.WG_PATH = process.env.WG_PATH || '/etc/wireguard/';
 module.exports.WG_DEVICE = process.env.WG_DEVICE || 'eth0';
 module.exports.WG_HOST = process.env.WG_HOST;
 module.exports.WG_PORT = process.env.WG_PORT || 51820;
-module.exports.WG_MTU = process.env.WG_MTU || null;
+module.exports.WG_MTU = process.env.WG_MTU || 1420;
 module.exports.WG_PERSISTENT_KEEPALIVE = process.env.WG_PERSISTENT_KEEPALIVE || 0;
 module.exports.WG_DEFAULT_ADDRESS = process.env.WG_DEFAULT_ADDRESS || '10.8.0.x';
 module.exports.WG_DEFAULT_DNS = typeof process.env.WG_DEFAULT_DNS === 'string'