It seems like your browser didn't download the required fonts. Please revise your security settings and try again.
Barracuda SSL VPN

How do I use my Clickatell SMS service with my Barracuda SSL VPN for One-Time Password?

  • Type: Knowledgebase
  • Date changed: 3 years ago

Solution #00004202



This solution applies to all Barracuda SSL VPNs.



To use Clickatell with a Barracuda SSL VPN for One-Time Password, follow these steps:


  1. Sign in to your Clickatell account at In the account, create an Email to SMS connection if one does not exist (the default is either XML or HTTP). Note the API_ID for this connection as you will need this later.
  2. In the SSL VPN, go to Basic > Configuration > SMTP.
  3. Set the outbound SMTP server and sender address (this is ideally a valid email address on the outbound server).
  4. Go to Access Control > Security Settings > One-Time Password.
  5. Set the method of password delivery to SMS over Email.
  6. Change the message text to the following:

    Where <username> is your clickatell username, <password> is your clickatell password, and <API_ID> is the API ID noted earlier.

    to: ${userAttributes:cellNumber}
    text:Your one time password is: ${otp:password}. This password expires on: ${otp:expiryDate}
  7. Change the expired message to:

    to: ${userAttributes:cellNumber}
    text:All OTPs have been revoked. You will now receive a password during the logon process.
  8. Click Save Changes.
  9. In the SMS section, set the SMS gateway address to
  10. Click Save Changes.

Additional Notes:

If you want to force this authentication scheme for a specific user, edit the user?s account in Access Control > Accounts and set their cell phone number attribute. Create an authentication scheme in Access Control > Authentication Schemes. Add the Password module first, followed by One-Time Password.


Log out and attempt to log in the user's account, who should then get a text message sent to their mobile phone when prompted for the One-Time Password. Note: You may have to define the mobile phone number in international format (e.g. +44 011 000 000 0000).


Link to this page: