A one-time password (OTP) is a password that is valid for only one login session, it can protect the password-based authentication from replay attacks. For the router's remote access (log in from the WAN interface), you may use OTP and add a layer of security to your router and the local network. This requires a device, usually a mobile phone, generating the one-time password.
1. Install a mOTP APP (e.g., mOTP - mobile OneTimePasswords) on your smart phone.
2. Create a new profile, define 4 digits PIN code and 16 digits Secret, then click Save.
3. On the router, go to System Maintenance >> Administrator Password Setup page, enter the PIN Code and same Secret defined in step 2.
4. When logging in to the router, first you need to generate the one time password on the mobile APP. Enter the same PIN Code on the app, then click Generate.
5. You can log into your router from the internet with this one time password, which is valid for one minute. You will need to generate the password again if the password expired.