DrayTek Vigor port knocking with TOTP
DrayTek Vigor routers can hide their management behind a time-based knock: the ports change every 30 seconds with a TOTP code. Secret Knock computes the code on your device and sends the knock the way DrayTek's own Port Knocking Tool does.
How the Vigor knock works
The router shows a TOTP key, usually as a QR code. Every 30 seconds that key gives a six-digit code. The knock is three TCP connection attempts: the first port you configured on the router, then 1000 plus the first three digits of the code, then 2000 plus the last three. The router then opens its management port, such as the web admin on 443, for your address.
Add the door in the app
- 1New door › Start from a template › DrayTek Vigor (sets the web admin, 443, as the port to check).
- 2Enter the router's first knock port and its TOTP key — the base32 key or the otpauth link. On iPhone and iPad, scan the router's QR code.
- 3The editor shows the current verification code, the one the router asks for while you set it up.
- 4Knock; the app computes the code at that moment.
Questions
Do the clocks need to match?
Yes, roughly: the code is based on the time, so your device and the router need the correct time.