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FortiGate IPSec VPN Tunnel Setup

Step 1: Access the Firewall GUI​

  1. Launch the firewall.
  2. Enter the public IP address of the firewall in a web browser.
  3. Login using the provided credentials:
    • Username: admin
    • Password: (Received via email)


Step 2: Create a New VPN Tunnel​

  1. Click on VPN Tunnels in the firewall dashboard.
  2. Click Create New.
  3. Select IPSec Tunnel from Template.
  4. Enter a name for the tunnel (e.g., VPC Peering).
  5. Click Begin.


Step 3: Configure IPSec Tunnel​

  1. Enter a Pre-shared Key (randomly generated). Example:
    4+w2vCVCAB7t6Po9hCwqA8dm
  2. Ensure the same passkey is used for both firewalls.
  3. Click Next.


Step 4: Configure Remote Firewall Settings​

  1. Enter the Public IP address of the remote firewall.
  2. Update the VPC CIDR of the remote firewall.
  3. Click Next.


Step 5: Configure Interface Settings​

  1. Set Outgoing Interface to port1.
  2. Set Local Interface to port2.
  3. Click Next.


Click on Next

It will show like below and click on submit



Step 6: Finalizing the Configuration​

  1. Click Submit.
  2. You may receive a 500: Internal Server Error message.
    • Ignore this and click Submit again.
  3. The firewall GUI may go down due to the tunnel using port 443.


Step 7: Change Firewall GUI Port

  1. Login to the firewall CLI.

Execute the following command to change the GUI port to 444:
config system global
set admin-sport 444

  1. end
  2. Access the firewall GUI using the new port:


https://164.52.220.91:444/

Please check the firewall policy has been added like below

Step 8: Configure the Second Firewall​

  1. Repeat the same steps on the second FortiGate firewall:
    • Update the Remote Firewall IP.
    • Update the Remote VPC CIDR.
    • Change the GUI port to 444 using CLI.
    • Verify that the firewall policies have been added correctly.

Step 9: Verify Configuration​

  1. Ensure that both firewalls have the VPN tunnel established.
  2. Check firewall policies to confirm that the VPC peering connection is configured properly.

Last updated on May 15, 2026.