Technical Tip: Behavior of custom IKE port

[Sindre-FTNT]

Description
This article describes how the parameter 'set ike-port' under config system settings works in FortiOS 7.0.
Solution
The behavior for set ike-port was changed with FortiOS 7.0.

Use the following commands:

# config system settings

    set ike-port (Custom port, 4500 or 500 (default))

end

FortiGate will handle the incoming IKE request as follows:

set ike-port X <----- Custom port example.

- Server listens on port X and port 4500.
- Initiator starts on port X.

set ike-port 500 <----- Default setting.

- Server listens on port 500 and 4500.
- Initiator starts on port 500.

set ike-port 4500

- Server listens on port 500 and 4500.

- Initiator starts on port 4500.