5.10.3. SMS Token Configuration

The SMS OTP token creates a OTP value and sends this OTP value to the mobile phone of the user. The SMS can be triggered by authenticating with only the OTP PIN: First step

In the first step the user will enter his OTP PIN and the sending of the SMS is triggered. The user is denied the access. Second step

In the second step the user authenticates with the OTP PIN and the OTP value he received via SMS. The user is granted access.

Alternatively the user can authenticate with the transaction_id that was sent to him in the response during the first step and only the OTP value. The transaction_id assures that the user already presented the first factor (OTP PIN) successfully.

A python SMS provider module defines how the SMS is sent. This can be done using an HTTP SMS Gateway. Most services like Clickatel or sendsms.de provide such a simple HTTP gateway. Another possibility is to send SMS via sipgate, which provides an XMLRPC API. The third possibility is to send the SMS via an SMTP gateway. The provider receives a specially designed email and sends the SMS accordingly. The last possibility to send SMS is to use an attached GSM modem.

Starting with version 2.13 the SMS configuration has been redesigned. You can now centrally define SMS gateways. These SMS gateways can be used for sending SMS OTP token but also for the event notifications. (See User Notification Handler Module)

For configuring SMS Gateways read SMS Gateway configuration. I this token configuration you can select on defined gateway to send SMS for authentication. Configuration Parameters

Concurrent Challenges

If set to True in The Config File, the config entry sms.concurrent_challenges will save the sent OTP value in the challenge database. This way several challenges can be open at the same time. The user can answer the challenges in an arbitrary order. Defaults to off.