Single Sign-On to Windows AD

Testing FSSO

Once FSSO is configured, you can easily test to ensure your configuration is working as expected. For additional FSSO testing, see Troubleshooting FSSO on page 140.

  1. Logon to one of the stations on the FSSO domain, and access an Internet resource.
  2. Connect to the CLI of the FortiGate unit, and if possible log the output.
  3. Enter the following command:diagnose debug authd fsso list
  4. Check the output. If FSSO is functioning properly you will see something similar to the following:

—-FSSO logons—-

IP: 192.168.1.230 User: ADMINISTRATOR Groups: VLAD-AD/DOMAIN USERS

IP: 192.168.1.240 User: ADMINISTRATOR Groups: VLAD-AD/DOMAIN USERS

Total number of users logged on: 2

—-end of FSSO logons—-

The exact information will vary based on your installation.

  1. Check the FortiGate event log, for FSSO-auth action or other FSSO related events with FSSO information in the message field.
  2. To check server connectivity, run the following commands from the CLI:

FGT# diagnose debug enable

FGT# diagnose debug authd fsso server-status

FGT# Server Name Connection Status      ———– —————–

SBS-2003 connected

Troubleshooting FSSO

Troubleshooting FSSO

When installing, configuring, and working with FSSO some problems are quite common. A selection of these problems follows including explanations and solutions.

Some common Windows AD problems include:

l General troubleshooting tips for FSSO l Users on a particular computer (IP address) can not access the network l Guest users do not have access to network

General troubleshooting tips for FSSO

The following tips are useful in many FSSO troubleshooting situations.

  • Ensure all firewalls are allowing the FSSO required ports through.

FSSO has a number of required ports that must be allowed through all firewalls or connections will fail. These include: ports 139, 389 (LDAP), 445, 636 (LDAP).

  • Ensure there is at least 64kbps bandwidth between the FortiGate unit and domain controllers. If there is insufficient bandwidth, some FSSO information might not reach the FortiGate unit. The best solution is to configure traffic shaping between the FortiGate unit and the domain controllers to ensure that the minimum bandwidth is always available.

Users on a particular computer (IP address) can not access the network

Windows AD Domain Controller agent gets the username and workstation where the logon attempt is coming from. If there are two computers with the same IP address and the same user trying to logon, it is possible for the authentication system to become confused and believe that the user on computer_1 is actually trying to access computer_2.

Windows AD does not track when a user logs out. It is possible that a user logs out on one computer, and immediate logs onto a second computer while the system still believes the user is logged on the original computer. While this is allowed, information that is intended for the session on one computer may mistakenly end up going to the other computer instead. The result would look similar to a hijacked session. Solutions

l Ensure each computer has separate IP addresses. l Encourage users to logout on one machine before logging onto another machine. l If multiple users have the same username, change the usernames to be unique. l Shorten timeout timer to flush inactive sessions after a shorter time.

Guest users do not have access to network

A group of guest users was created, but they don’t have access.

Troubleshooting FSSO

Solution

The group of the guest users was not included in a policy, so they do not fall under the guest account. To give them access, associate their group with a security policy.

Additionally, there is a default group called SSO_Guest_Users. Ensure that group is part of an identity-based security policy to allow traffic.

 


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This entry was posted in FortiGate, FortiOS 5.6 on by .

About Mike

Michael Pruett, CISSP has a wide range of cyber-security and network engineering expertise. The plethora of vendors that resell hardware but have zero engineering knowledge resulting in the wrong hardware or configuration being deployed is a major pet peeve of Michael's. This site was started in an effort to spread information while providing the option of quality consulting services at a much lower price than Fortinet Professional Services. Owns PacketLlama.Com (Fortinet Hardware Sales) and Office Of The CISO, LLC (Cybersecurity consulting firm).

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