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Barracuda CloudGen Firewall

This Firmware Version Is End-Of-Support

Documentation for this product is no longer updated. Please see End-of-Support for CloudGen Firewall Firmware for further information on our EoS policy.

How to Configure the SSL VPN Service

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The SSL VPN service is part of the VPN service on the F-Series Firewall. Configure the SSL VPN to listen on a public IP address and to authenticate the users via a local or external authentication. It is recommended to use signed SSL certificates to avoid SSL error messages. SSL VPN is supported for Barracuda NextGen Firewall F80 and larger, as well as all Barracuda NextGen Firewall F-Series Vx models except VF10. 

Before you begin

  • A remote access premium subscription is required.
  • Verify that the IP address you want the SSL VPN to listen on is configured as a virtual server and VPN service IP address. For more information, see Virtual Servers and Services
  • Configure an external authentication server or NGF local authentication. For more information, see Authentication.

Step 1. Disable port 443 for site-to-site and client-to-site VPN 

  1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN > VPN Settings.
  2. Click Lock.
  3. Click Click here for Server Settings link. The Server Settings window opens.
  4. Set Use Port 443 to No.
  5. Click OK.
  6. Click Send Changes and Activate.

Step 2. Configure SSL VPN general service settings

Enable SSL VPN service and add the listening IP addresses

  1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > SSL-VPN.
  2. Click Lock.
  3. Set Enable SSL VPN to Yes.

  4. (optional) Set Enable CudaLaunch to yes.
  5. Click + to add a Listen IP.

  6. (recommended) Enable Restrict to Strong Ciphers Only.

  7. Select the Identification Type
    • Generated-Certificate – The certificate and the private key is automatically created by the firewall.
    • Self-Signed-Certificate – Click New to create a Self-Signed Private Key and then Edit to create the Self-Signed Certificate.
    • External-Certificate – Click Ex/Import  to import the CA-signed External Certificate and the External-Signed Private Key.
  8. Click Send Changes and Activate.

Step 3. Configure authentication and login

Configure user authentication and optionally configure which user groups are allowed. Users that are not members of one of these groups will be denied access to the SSL VPN.

  1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > SSL-VPN .
  2. In the left menu, click Authentication & Login.
  3. Click Lock.
  4. From the  Authentication Scheme list, select your authentication method.   
  5. If you are using an authentication service with group information, or an authentication helper scheme to provide group information, set Use Group Policies to yes.
  6. (optional) Click + to add Allowed User Groups.  

    To allow all user groups add a * wildcard entry. If the Allowed User Groups list is empty, all users are blocked.

  7. (optional) Click + to add Blocked User Groups.   
  8. (optional) Configure the following settings as needed:  
    • Use Max Concurrent Users – Enable to limit the number of simultaneous users using the NextGen F-Series SSL VPN.
    • Max Concurrent Users – Enter the maximum number of users that simultaneously can be connected to the NextGen F-Series SSL VPN. 
    • Cookie Timeout (Min) – Enter the session timeout in minutes.
    • Authentication Request Timeout (sec) to a value up to 20 seconds if you are using multi-factor authentication.            
    • Deny Remember Me – Set to yes to remove the Remember me checkbox on the login page.
  9. Customize the login messages and logos:   
    • (optional) Import 200 x 66px PNG or JPG image to customize the Logo.

    • (optional) Enter a plain text Login Message. E.g, Welcome to the Barracuda NextGen Firewall SSL VPN.
    • (optional) Enter a HTML Help Text.
  10. Click Send Changes and Activate.

Step 4. (optional) Use custom cipher string

If needed you can configure a custom cipher string to be used by the SSL VPN service.

  1. Go to CONFIGURATION > Configuration Tree > Box > Virtual Servers > your virtual server > Assigned Services > VPN-Service > SSL-VPN.
  2. Click Lock.
  3. In the left menu expand Configuration Mode and click on Switch to Advanced View.
  4. Disable Allow SSLv3.

  5. Enable Restrict to Strong Ciphers Only.

  6. Enter your custom SSL Cipher Spec string. 

  7. Set Strict SSL Security to yes.

    This setting may break access for some older client SSL implementation. Disable if you experience problems when using older browsers.

  8. Click Send Changes and Activate.


  • If the sslvpn log contains the following line: http_listener: failed to listen on @443 verify that no other service on the Barracuda NextGen Firewall F-Series is running on that port and no DNAT access rules are forwarding TCP port 443 (HTTPS) traffic.
  • When updating or changing certificates, the SSL VPN service needs to be restarted:
    1.  Set Enable SSL VPN to no.
    2.  Click Send Changes and Activate.
    3.  Set Enable SSL VPN to yes.
    4.  Click Send Changes and Activate.
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