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Barracuda CloudGen Firewall

How to Configure NTLM Authentication

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Integrate the Barracuda CloudGen Firewall with your NT LAN Manager (NTLM) authentication server to authenticate NTLM domain users via their Microsoft Windows credentials. To enable transparent authentication against your NTLM server, join the firewall to the NTLM domain as an authorized host.

Step 1. Configure NTLM Authentication

  1. Go to USERS > External Authentication.

  2. Click the NTLM tab.

  3. Enter the NTLM/Kerberos realm name in the Domain Realm field.

    Always enter the Domain Realm in uppercase letters. E.g., MYDOMAIN.COM

  4. Enter the Netbios Domain Name.

  5. (Optional) Enter the MS Active Directory Workgroup Name.

  6. In the Domain Controller field, enter the hostname or IP address of the domain controller.

    The hostname must be DNS resolvable.

  7. (Optional) Enter the hostname of the domain's Windows Internet Name Service server in the WINS Servers field.

  8. Select the authentication scheme to retrieve group information from.

  9. Click Save.

The configuration is now added to the Existing Authentication Services table.

Step 2. Join the Firewall to the Domain

Join the CloudGen Firewall to the NTLM domain as an authorized host.

  1. Go to USERS > External Authentication.
  2. Click the NTLM tab.
  3. Enter the Windows Domain Username.
  4. Enter the Windows Domain Password.
  5. Click Save.
  6. Click Join Domain.


You can check the status of the domain registration by clicking Registration Status.

Your NTLM domain users can now authenticate on the firewall using their Microsoft Windows credentials.

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