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:

• General troubleshooting tips for FSSO
• Users on a particular computer (IP address) can not access the network
• 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

• Ensure each computer has separate IP addresses.
• Encourage users to logout on one machine before logging onto another machine.
• If multiple users have the same username, change the usernames to be unique.
• 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.

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.

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 551.

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.

5. Check the FortiGate event log, for FSSO-auth action or other FSSO related events with FSSO information in the message field.

6. 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

FortiOS FSSO log messages

There are two types of FortiOS log messages — firewall and event. FSSO related log messages are generated from authentication events. These include user logon and log off events, and NTLM authentication events. These log messages are central to network accounting policies, and can also be useful in troubleshooting issues. For more information on firewall logging, see Enabling security logging on page 507. For more information on logging, see the FortiOS Handbook Logging and Reporting guide.

Enabling authentication event logging

For the FortiGate unit to log events, that specific type of event must be enabled under logging.

When VDOMs are enabled certain options may not be available, such as CPU and memory usage events. You can enable event logs only when you are logged on to a VDOM; you cannot enable event logs globally.

To ensure you log all the events needed, set the minimum log level to Notification or Information. Firewall logging requires Notification as a minimum. The closer to Debug level, the more information will be logged.

To enable event logging:

1. Go to Log&Report > Log Config > Log Settings.

2. In Event Logging, select

System activity event              All system-related events, such as ping server failure and gateway status.

User Activity event                   All administration events, such as user logins, resets, and configuration updates.

3. Select Apply.

List of FSSO related log messages

For more information on logging, see the FortiOS Handbook Logging and Reporting guide.

Creating security policies

Policies that require FSSO authentication are very similar to other security policies. Using identity-based policies, you can configure access that depends on the FSSO user group. This allows each FSSO user group to have its own level of access to its own group of services

In this situation, Example.com is a company that has its employees and authentication servers on an internal network. The FortiGate unit intercepts all traffic leaving the internal network and requires FSSO authentication to access network resources on the Internet. The following procedure configures the security policy for FSSO authentication. FSSO is installed and configured including the RADIUS server, FSSO Collector agent, and user groups on the FortiGate

For the following procedure, the internal interface is port1 and the external interface connected to the Internet is port2. There is an address group for the internal network called company_network. The FSSO user group is called fsso_group, and the FSSO RADIUS server is fsso_rad_server.

To configure an FSSO authentication security policy – web-based manager:

1. Go to Policy & Objects > Policy > IP4 and select Create New.

2. Enter the following information.

Incoming Interface                   port1

Source Address                        company_network

Source User(s)                          fsso_group

Outgoing Interface                   port2

Destination Address                 all

Schedule                                    always

Service                                       HTTP, HTTPS, FTP, and Telnet

Action                                         ACCEPT

NAT                                             ON

UTM Security Profiles              ON for AntiVirus, IPS, Web Filter, and Email Filter, all using default pro- files.

Log Allowed Traffic                  ON. Select Security Events.

3. Select OK.

4. Ensure the FSSO authentication policy is higher in the policy list than more general policies for the same interfaces.

To create a security policy for FSSO authentication – CLI:

config firewall policy edit 0

set srcintf port1 set dstintf port2

set srcaddr company_network set dstaddr all

set action accept

set groups fsso_group set schedule always

set service HTTP HTTPS FTP TELNET

set nat enable end

Here is an example of how this FSSO authentication policy is used. Example.com employee on the internal company network logs on to the internal network using their RADIUS username and password. When that user attempts to access the Internet, which requires FSSO authentication, the FortiGate authentication security policy intercepts the session, checks with the FSSO Collector agent to verify the user’s identity and credentials, and then if everything is verified the user is allowed access to the Internet.

Enabling guest access through FSSO security policies

You can enable guest users to access FSSO security policies. Guests are users who are unknown to Windows AD and servers that do not logon to a Windows AD domain.

To enable guest access in your FSSO security policy, add an identity-based policy assigned to the built-in user group SSO_Guest_Users. Specify the services, schedule and UTM profiles that apply to guest users — typically guests have access to a reduced set of services. See Creating security policies on page 548.