SSL VPN with LDAP user password renew

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SSL VPN with LDAP user password renew

This topic provides a sample configuration of SSL VPN for LDAP users with Force Password Change on next logon. In this example, the LDAP server is a Windows 2012 AD server. A user ldu1 is configured on Windows 2012 AD server with Force password change on next logon.

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 network 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 SSL VPN connection is established over the WAN interface.

To configure SSL VPN using the GUI:

  1. Configure the interface and firewall address. Port1 interface connects to the internal network.
    1. Go to Network > Interface and edit the wan1
    2. Set IP/Network Mask to 20.120.123/255.255.255.0.
    3. Edit port1 interface and set IP/Network Mask to 168.1.99/255.255.255.0.
    4. Click OK.
    5. Go to Firewall & Objects > Address and create an address for internet subnet 168.1.0.
  2. Import CA certificate into FortiGate.
    1. Go to System > Features Visibility and enable Certificates.
    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.

  1. 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

  1. Configure the LDAP user.
    1. Go to User& Device > LDAP Servers > Create New.
      • Specify Name and ServerIP/Name.
      • Specify Common Name Identifier, Distinguished Name. l Set Bind Type to Regular. l Specify Username and Password. l Enable Secure Connection and set Protocol to LDAPS. l For Certificate, select LDAP serverCA LDAPS-CA from the list.
    2. To enable the password-renew option, use these CLI commands.

config user ldap edit “ldaps-server” set password-expiry-warning enable set password-renewal enable

next

end

  1. Configure user group.
    1. Go to User& Device > UserGroups to create a user group.
    2. Enter a Name.
    3. In Remote Groups, click Add to add ldaps-server.
  2. Configure SSL VPN web portal.
    1. Go to VPN > SSL-VPN Portals to edit the full-access

This portal supports both web and tunnel mode.

  1. Disable Enable Split Tunneling so that all SSL VPN traffic goes through the FortiGate.
  1. Configure SSL VPN settings.
    1. Go to VPN > SSL-VPN Settings.
    2. Choose proper Listen on Interface, in this example, wan1.
    3. Listen on Port 10443.
    4. Set ServerCertificate to the authentication certificate.
    5. Under Authentication/Portal Mapping, set default Portal web-access for All OtherUsers/Groups.
    6. Create new Authentication/Portal Mapping for group ldaps-group mapping portal full-access.
  2. Configure SSL VPN firewall policy.
    1. Go to Policy & Objects > IPv4 Policy.
    2. Fill in the firewall policy name, in this example, sslvpn certificate auth.
    3. Incoming interface must be SSL-VPN tunnel interface(ssl.root).
    4. Set the Source Address to all and Source User to ldaps-group.
    5. Set the Outgoing Interface to the local network interface so that the remote user can access the internal network, in this example, port1.
    6. Set Destination Address to the internal protected subnet 168.1.0.
    7. Set schedule to always, service to ALL, and Action to Accept.
    8. Enable NAT.
    9. Configure any remaining firewall and security options as desired.
    10. Click OK.

To configure SSL 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

Configure internal interface and protected subnet.

Connect Port1 interface to 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 subnet192.168.1.0 255.255.255.0

next

end

  1. Import CA certificate into FortiGate.
    1. Go to System > Features Visibility and enable Certificates.
    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.

  1. 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

  1. 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 ENC

Uf/OvqAbjSpeZz4wv9Tapl3xyMn1DGSTSxb2ZAB5dA5kVd0wVsGaeAhuX1Hl7mRtJQdRL8L2mzSfV6NTyQsdJ8E+rZy mImS2rfQg0OZ0IRRYKp0v3qFXgsmW9x9xRP2u79OcpUR5JmnnW8DFnK9jSUGix+DvYpbBn8EwweoDQq55Ej9FLwKSBY iYZs18V9ktSxT49w== set group-member-check group-object

set secure ldaps set ca-cert “LDAPS-CA” set port 636

set password-expiry-warning enable set password-renewal enable

next

end

  1. Configure user group.

config user group edit “ldaps-group” set member “ldaps-server”

next end

  1. Configure SSL VPN web portal.

config vpn ssl web portal edit “full-access” set tunnel-mode enable set web-mode enable set ip-pools “SSLVPN_TUNNEL_ADDR1” set split-tunneling disable

next

end

  1. Configure SSL VPN settings.

config vpn ssl settings set servercert “server_certificate” set tunnel-ip-pools “SSLVPN_TUNNEL_ADDR1” set source-interface “wan1” set source-address “all” set default-portal “web-access” config authentication-rule edit 1 set groups “ldaps-group” set portal “full-access”

next

end

  1. Configure SSL VPN firewall policy.

Configure one firewall policy to allow remote user to access the internal network.

config firewall policy edit 1 set name “sslvpn web mode access”

set srcintf “ssl.root” set dstintf “port1” set srcaddr “all” set dstaddr “192.168.1.0” set groups “ldaps-group” set action accept set schedule “always” set service “ALL” set nat enable

next

end

To see the results of the SSL VPN web connection:

  1. From a remote device, open a web browser and log into the SSL VPN web portal http://172.20.120.123:10443.
  2. Log in using the ldu1

Use a user which is configured on FortiAuthenticator with Force password change on next logon.

  1. Click Login. You are prompted to enter a new password.
  2. Go to VPN > Monitor> SSL-VPN Monitor to verify the user’s connection.

To see the results of the SSL VPN tunnel connection:

  1. Download FortiClient from forticlient.com.
  2. Open the FortiClient Console and go to Remote Access > Configure VPN.
  3. Add a new connection.
    • Set the connection name.
    • Set Remote Gateway to the IP of the listening FortiGate interface, in this example, 20.120.123.
  4. Select Customize Port and set it to 10443.
  5. Save your settings.
  6. Log in using the ldu1

You are prompted to enter a new password.

To check the SSL VPN connection using the GUI:

  1. Go to VPN > Monitor> SSL-VPN Monitor to verify the user’s connection.
  2. Go to Log & Report > VPN Events to view the details of the SSL VPN connection event log.
  3. Go to Log & Report > Forward Traffic to view the details of the SSL VPN traffic.

To check the web portal login using the CLI:

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

SSL VPN sessions:

 10.1.100.254 0/0       0/0
Index User       Source IP      Duration

To check the tunnel login using the CLI:

get vpn ssl monitor

SSL VPN Login Users:

 I/O Bytes        Tunnel/Dest IP
Index User       Auth Type      Timeout From      HTTP in/out   HTTPS in/out
0        ldu1          1(1)            291

SSL VPN sessions:

 10.1.100.254 0/0       0/0
Index User       Source IP      Duration I/O Bytes        Tunnel/Dest IP
0        ldu1          10.1.100.254    9 22099/43228    10.212.134.200

Having trouble configuring your Fortinet hardware or have some questions you need answered? Check Out The Fortinet Guru Youtube Channel! Want someone else to deal with it for you? Get some consulting from Fortinet GURU!

This entry was posted in Administration Guides, FortiGate, FortiOS 6.2 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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