Setting up a Virtual Private Network (VPN) using Fortinet’s FortiGate firewall enhances secure remote access to your network. This comprehensive guide will walk you through configuring both SSL VPN and IPsec VPN, utilizing Fortinet’s resources and best practices.

1. Prerequisites

Before proceeding, ensure you have:

  • Administrative access to the FortiGate firewall.
  • A public IP address or domain name for the FortiGate’s external interface.
  • User credentials for VPN access.

2. Configuring SSL VPN

SSL VPN allows users to securely connect to the internal network via a web browser or FortiClient.

a. Enable SSL VPN on the FortiGate

  1. Log in to the FortiGate GUI.
  2. Navigate to VPN > SSL-VPN Settings.
  3. Set the Listen on Interface(s) to the external interface (e.g., wan1).
  4. Specify the Listen on Port (default is 443).
  5. Configure the Server Certificate.
  6. Define the IP Ranges for SSL VPN clients.
  7. Set the Authentication/Portal Mapping by selecting user groups and assigning portals.

b. Create User Accounts and Groups

  1. Go to User & Device > User Definition.
  2. Click Create New to add users.
  3. Navigate to User & Device > User Groups.
  4. Create a new group and add the users.

c. Configure SSL VPN Policies

  1. Go to Policy & Objects > IPv4 Policy.
  2. Create a new policy:
    • Incoming Interface: SSL-VPN tunnel interface.
    • Outgoing Interface: Internal network interface.
    • Source: SSL VPN user group.
    • Destination: Internal network.
    • Service: All.
    • Action: Accept.
  3. Enable NAT if required.

d. Client Configuration

Users can connect using FortiClient:

  1. Download and install FortiClient from Fortinet’s official site.
  2. Open FortiClient and navigate to Remote Access.
  3. Add a new connection:
    • VPN Type: SSL-VPN.
    • Remote Gateway: FortiGate’s public IP or domain.
    • Port: As configured (default 443).
  4. Save and connect using user credentials.

3. Configuring IPsec VPN

IPsec VPN provides secure site-to-site or client-to-site connections.

a. Using the IPsec VPN Wizard

  1. In the FortiGate GUI, go to VPN > IPsec Wizard.
  2. Select the VPN Setup type:
    • Remote Access for client-to-site.
    • Site to Site for connecting two networks.
  3. Follow the wizard steps:
    • Authentication Method: Pre-shared Key or Certificate.
    • Policy & Routing: Define local and remote networks.
    • Security Policy: Configure encryption and authentication settings.

b. Manual Configuration

  1. Phase 1 Configuration:
    • Go to VPN > IPsec Tunnels.
    • Click Create New.
    • Set Remote Gateway, Interface, and Authentication.
    • Configure IKE Version, Mode, and Proposal settings.
  2. Phase 2 Configuration:
    • Within the same tunnel, configure Phase 2 Selectors.
    • Define Encryption and Authentication algorithms.
    • Set Quick Mode Selectors for local and remote subnets.
  3. Firewall Policies:
    • Create policies to allow traffic between local and remote networks.

c. Client Configuration

For client-to-site IPsec VPN:

  1. In FortiClient, go to Remote Access.
  2. Add a new connection:
    • VPN Type: IPsec VPN.
    • Remote Gateway: FortiGate’s public IP or domain.
    • Authentication: Pre-shared Key or Certificate.
  3. Save and connect using user credentials.

4. Best Practices

  • Use Strong Authentication: Implement two-factor authentication (2FA) for enhanced security.
  • Restrict Access: Limit VPN access to necessary users and services.
  • Regular Updates: Keep FortiGate firmware and FortiClient updated.
  • Monitor Logs: Regularly review VPN logs for unusual activities.

For detailed configurations and advanced settings, refer to Fortinet’s official documentation: