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Chapter 4. VPN

4.2 SSL VPN

Learning Objectives

  • Configure a tunnel-based SSL VPN
  • Configure a web-based SSL VPN (Web Portal)
Scenario: We are going to have SSL VPN from Windows to FortiGate Firewall. First, we will install FortiClient on Windows and then we will configure the firewall for FortiClient. We have two types of SSL VPN, Web based mode and Tunnel mode. Web based mode doesn’t need any agents and you should be able to reach WordPress and SSH Server from Windows. Tunnel mode is through FortiClient. The goal of this scenario is to have connectivity from Windows to WordPress and SSH Server.
SSL VPN main scenario
Figure 4.38: Main scenario
Table 4.3: Devices configuration
Device IP address Access
FortiGate Port3: 192.168.1.1/24 – DHCP (192.168.1.20 to 192.168.1.30)

Port2: DHCP Client

 ICMP-HTTP-HTTPS
WebTerm (FMC) 192.168.1.2/24 –
KALI Linux (SSH Server) 192.168.1.3/24 –
WordPress 192.168.1.4/24
KALI-outside DHCP Client
Windows DHCP Client

Configure the interfaces of the firewall. Port2 and Port3 should be configured in the terminal to access the firewall.

  1. Port 3 Configuration:
    Port3 settings
    Figure 4.39: Port3 settings
  2. Port 2 Configuration:
    Port2 settings
    Figure 4.40: Port2 settings
  3. Configure DHCP Server on port3.
    Configure DHCP Server on port3
    Figure 4.41: Enable DHCP Server on port3
  4. Configure user and user group. Go to User & Authentication > User Definition to create a local user sslvpnuser1.
    Step1- Create a Local User
    Figure 4.42: Create a local user
    Configure Login Credentials
    Figure 4.43: Configure login credentials

    Go to User & Authentication > User Groups to create a group sslvpngroup with the member sslvpnuser1.

    Create a group
    Figure 4.44: Create a group
  5. Configure SSL VPN web portal and Tunnel mode. Go to VPN > SSL-VPN Portals:
    • Split-Tunneling: Disabled
    • Source IP Pools: SSLVPN_TUNNEL_ADDR1
    SSL-VPN Portal
    Figure 4.45: SSL-VPN Portal

    Go to VPN > SSL-VPN Portals, add KALI IP address (SSH Server: IP Address of Kali) and WordPress (IP Address of WordPress) in the bookmark section.

    Create a SSH bookmark
    Figure 4.46: Create an SSH bookmark
    Create a HTTP/HTTPS bookmark
    Figure 4.47: Create an HTTP/HTTPS bookmark
    Bookmark settings
    Figure 4.48: Bookmark settings
  6. Configure SSL VPN settings. Go to VPN > SSL-VPN Settings:
    • For Listen on Interface(s), select Port2.
    • Set Listen on Port to 8080.
    • Server Certificate: Fortinet
    • In restrict Access, select “Allow access from any host”
    • Address range: Automatically assign address.
    • In Authentication/Portal Mapping All Other Users/Groups, set the Portal to MyPortal
    • Create new Authentication/Portal Mapping for group sslvpngroup mapping portal MyPortal.
    Enable SSL-VPN Settings
    Figure 4.49: Enable SSL-VPN Settings
    Assign sslvpngroup to MyPortal
    Figure 4.50: Assign sslvpngroup to MyPortal
    Authentication/Portal Mapping
    Figure 4.51: Authentication/Portal Mapping
  7. Configure SSL VPN firewall policy:
    1. Go to Policy & Objects > Firewall Policy.
    2. Fill in the firewall policy name. In this example, SSLVPN full tunnel access.
    3. The incoming interface must be SSL-VPN tunnel interface(ssl.root).
    4. Choose an Outgoing Interface. In this example, port3.
    5. Set the Source to all and group to sslvpngroup.
    6. Set the Destination to all.
    7. Set Schedule to always, Service to ALL, and Action to Accept.
    Configure SSL VPN firewall policy
    Figure 4.52: Create a Firewall Policy for SSLVPN
  8. Now connect to Kali outside and open the browser https://IP-PORT 2-Firewall:8080
    Enter the username and password you created earlier. Then try to connect to the KALI SSH Server and WordPress through the browser.

    SSL VPN Portal
    Figure 4.53: SSL-VPN Portal
    SSL VPN Portal
    Figure 4.54: SSL-VPN Portal
    Verify WordPress
    Figure 4.55: Verify WordPress
    Verify SSH
    Figure 4.56: Verify SSH
  9. Now, go to Windows and install FortiClient on Windows. Try to use FortiClient to connect through SSLVPN.
    Download FortiClient
    Figure 4.57: Download FortiClient
    FortiClient Installation
    Figure 4.58: FortiClient Installation
    FortiClient Installation
    Figure 4.59: FortiClient Installation
  10. Configure FortiClient.
    Configure FortiClient
    Figure 4.60: Configure FortiClient
    Configure SSLVPN
    Figure 4.61: Configure SSLVPN
  11. Verify configuration. Enter the Username and Password you have set for SSLVPN.
    SSLVPN Credentials
    Figure 4.62: SSLVPN Credentials

    Accept the Certificate Issuer to have a secure connection.

    Accept the Certificate Issuer to have a secure connection
    Figure 4.63: Click on Yes in Security Alert
    Verify SSL VPN Connection
    Figure 4.64: Verify SSLVPN Connection

    Verify your connectivity by entering the IP address of WordPress.

    Verify your connectivity by entering the IP address of WordPress
    Figure 4.65: Verify WordPress

    Verify your connectivity by entering the IP address of SSH Server.

    Verify your connectivity by entering the IP address of SSH Server
    Figure 4.66: Verify SSH
    Verify SSH connection
    Figure 4.67: Verify SSH connection

License

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FortiGate Firewall Copyright © 2023 by Hamid Talebi is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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