Agentless VPN with LDAP user authentication

This is a sample configuration of Agentless VPN for LDAP users. In this example, the LDAP server is a Windows 2012 AD server. A user ldu1 is configured on Windows 2012 AD server.

You must have generated and exported a CA certificate from the AD server and then have imported it as an external CA certificate into the FortiGate.

Sample topology

Sample configuration

WAN interface is the interface connected to ISP. This example shows static mode. You can also use DHCP or PPPoE mode. The Agentless VPN connection is established over the WAN interface.

To configure Agentless VPN using the GUI:

1. Configure the interface and firewall address. The port1 interface connects to the internal network:

   1. Go to Network > Interfaces and edit the wan1 interface.

   2. Set IP/Network Mask to 172.20.120.123/255.255.255.0.

   3. Edit port1 interface and set IP/Network Mask to 192.168.1.99/255.255.255.0.

   4. Click OK.

   5. Go to Policy & Objects > Address and create an address for internet subnet 192.168.1.0.

2. Import CA certificate into FortiGate:

   1. Go to System > Features Visibility and ensure Certificates is enabled.

   2. Go to System > Certificates and select Import > CA Certificate.

   3. Select Local PC and then select the certificate file.

      The CA certificate now appears in the list of External CA Certificates. In this example, it is called CA_Cert_1.

   4. If you want, you can use CLI commands to rename the system-generated CA_Cert_1 to be more descriptive:

      config vpn certificate ca
          rename CA_Cert_1 to LDAPS-CA
      end

3. Configure the LDAP user:

   1. Go to User & Authentication > LDAP Servers and click Create New.

   2. Specify Name and Server IP/Name.

   3. Specify Common Name Identifier and Distinguished Name.

   4. Set Bind Type to Regular.

   5. Specify Username and Password.

   6. Enable Secure Connection and set Protocol to LDAPS.

   7. For Certificate, select LDAP server CA LDAPS-CA from the list.

4. Configure user group:

   1. Go to User & Authentication > User Groups to create a user group.

   2. Enter a Name.

   3. In Remote Groups, click Add to add ldaps-server.

5. Configure Agentless VPN portals.

   1. Go to VPN > Agentless VPN Portals, and click Create New.

   2. Enter a name, such as agentless-portal.

   3. Under Predefined Bookmarks, click Create New, and enter the following details:

      Field	Value
      Name	Windows Server
      Type	RDP
      Host	192.168.1.114
      Port	3389
      Single Sign-On	Disable
      Username	Set the username to log in to Windows Server.
      Password	Set the password to log in to Windows Server.
      Port	3389

   4. Click OK to save the predefined bookmark.

   5. Click OK to save the portal settings.

   6. Create another Agentless VPN portal and name it portal-access-disabled.

   7. Click OK to save the portal settings.

   8. Disable Agentless VPN for the newly created portal (that is, portal-access-disabled) using CLI:

      config vpn ssl web portal
          edit "portal-access-disabled"
              set web-mode disable
          next
      end

6. Configure Agentless VPN settings.

   1. Go to VPN > Agentless VPN Settings.

   2. Set Agentless VPN status to Enable.

   3. Set Listen on Interface(s) to wan1.

   4. Set Listen on Port to 10443.

   5. Choose a certificate for Server Certificate. The default is Fortinet_Factory.

   6. In Authentication/Portal Mapping, select All Other Users/Groups, and click Edit.

   7. Use Portal dropdown to select portal-access-disabled.

   8. Click OK.

   9. In Authentication/Portal Mapping, click Create New.

      1. Set Users/Groups to ldaps-server.

      2. Set Portal to agentless-portal.

      3. Click OK.

   10. Click Apply to save the Agentless VPN settings.

7. Configure Agentless VPN firewall policy.

   1. Go to Policy & Objects > Firewall Policy, and click Create New.

   2. Set Name to Agentless VPN firewall policy.

   3. Set Schedule to always and Action to Accept.

   4. Set Incoming interface to Agentless VPN interface (ssl.root).

   5. Choose an Outgoing Interface. This example uses port1.

   6. Set the Source to all and User/group to ldaps-group.

   7. In this example, the Destination is the internal, protected subnet 192.168.1.0.

   8. Set Service to ALL.

   9. Enable NAT.

   10. Configure any remaining firewall and security options as desired.

   11. Click OK.

To configure Agentless VPN using the CLI:

1. Configure the interface and firewall address:

   config system interface 
       edit "wan1"
           set vdom "root"
           set ip 172.20.120.123 255.255.255.0
       next
   end

2. Configure internal interface and protected subnet, then connect the port1 interface to the internal network:

   config system interface
       edit "port1"
           set vdom "root"
           set ip 192.168.1.99 255.255.255.0
       next
   end

   config firewall address
       edit "192.168.1.0"
           set subnet 192.168.1.0 255.255.255.0
       next
   end

3. Import CA certificate into FortiGate:

   1. Go to System > Features Visibility and ensure Certificates is enabled.

   2. Go to System > Certificates and select Import > CA Certificate.

   3. Select Local PC and then select the certificate file.

      The CA certificate now appears in the list of External CA Certificates. In the example, it is called CA_Cert_1.

   4. If you want, you can use CLI commands to rename the system-generated CA_Cert_1 to be more descriptive:

      config vpn certificate ca
          rename CA_Cert_1 to LDAPS-CA
      end

4. Configure the LDAP server:

   config user ldap
       edit "ldaps-server"
           set server "172.20.120.161"
           set cnid "cn"
           set dn "cn=Users,dc=qa,dc=fortinet,dc=com"
           set type regular
           set username "CN=Administrator,cn=users,DC=qa,DC=fortinet,DC=com"
           set password **********
           set group-member-check group-object
           set secure ldaps
           set ca-cert "LDAPS-CA"
           set port 636
       next
   end

5. Configure user group:

   config user group
       edit "ldaps-group"
           set member "ldaps-server"
       next
   end

6. Configure Agentless VPN portal and predefine RDP bookmark for windows server.

   config vpn ssl web portal
       edit "agentless-portal"
           set web-mode enable
           config bookmark-group
               edit "gui-bookmarks"
                   config bookmarks
                       edit "Windows Server"
                           set apptype rdp
                           set host "192.168.1.114"
                           set port 3389
                           set logon-user "your-windows-server-user-name"
                           set logon-password your-windows-server-password
                       next
                   end
               next
           end
       next
   end

7. Configure another Agentless VPN portal and disable Agentless VPN on it.

   config vpn ssl web portal
       edit "portal-access-disabled"
           set web-mode disable
       next
   end

8. Configure Agentless VPN settings:

   config vpn ssl settings
       set banned-cipher SHA1 SHA256 SHA384
       set servercert "server_certificate"
       set port 1443   
       set source-interface "wan1"
       set source-address "all"
       set default-portal "portal-access-disabled"
       config authentication-rule
           edit 1
               set groups "ldaps-group"
               set portal "agentless-portal"
           next        
       end
   end

9. Configure one Agentless VPN firewall policy to allow remote user to access the internal network. The policy does not allow traffic initiated from internal network to remote client:

   config firewall policy 
       edit 1
           set name "Agentless VPN firewall policy"
           set srcintf "ssl.root"
           set dstintf "port1"
           set srcaddr "all"
           set dstaddr "192.168.1.0"        
           set action accept
           set schedule "always"
           set service "ALL"
           set nat enable
           set groups "ldaps-group"
       next
   end

To see the results of Agentless VPN portal access:

1. From a remote device, use a web browser to log into the Agentless VPN portal http://172.20.120.123:10443.

2. Enter the ldu1 user credentials, then click Login.

3. On FortiGate, go to Dashboard > Agentless VPN Monitor to verify the list of Agentless VPN users.

   If the Agentless VPN Monitor is hidden, click + under the Dashboard, search for Agentless VPN Monitor, and add it to the display.

4. Go to Log & Report > System Events, and use the dropdown to select VPN Events to view VPN logs.

To check the Agentless VPN portal login using the FortiOS CLI:

# get vpn ssl monitor
Agentless VPN Login Users:
 Index   User    Auth Type    Timeout    From           HTTP in/out  HTTPS in/out
 0       ldu1    1(1)         229        10.1.100.254   0/0          0/0

Agentless VPN sessions:
 Index   User    Source IP      Duration        I/O Bytes       Tunnel/Dest IP