Technical Tip: Behavior of custom IKE port

Description

This article describes how the parameter 'set ike-port' under config system settings works in FortiOS v7.0.

Scope

FortiGate.

Solution

The behavior for set ike-port was changed with FortiOS v7.0.

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 ports X and 4500.
• Initiator starts on port X.

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

• Server listens on ports 500 and 4500.
• Initiator starts on port 500.

    set ike-port 4500

• Server listens on ports 500 and 4500.
• Initiator starts on port 4500.