What UDP Port is Used for IKE Traffic from VPN Client to Server?

If you’re wondering what UDP port is used for IKE traffic from VPN clients to servers, you’re in the right place. Keep reading to find out.

What UDP Port is Used for IKE Traffic from VPN Client to Server?Checkout this video:


The IKE (Internet Key Exchange) key management protocol is essential for establishing a secure VPN connection. IKE uses a variety of protocols and algorithms to generate keys and exchange them between the VPN client and server. One of the most important aspects of IKE is the negotiation process, during which the client and server decide on the appropriate security protocols and algorithms to use.

One of the key parameters that must be negotiated during IKE is the UDP port that will be used for IKE traffic. By default, IKE uses UDP port 500 for this purpose. However, some firewalls block UDP port 500, making it impossible to establish a VPN connection. In these cases, it may be necessary to change the IKE UDP port to a different value.

The following table lists some common values that can be used for the IKE UDP port:

-UDP port 500
-UDP port 4500
-UDP port 4501
-UDP port 5505

The Three Main Components of an IKE VPN

IKE VPNs are composed of three main components:
-A security association (SA) database, used to keep track of all the security associations for a particular VPN.
-A key exchange daemon (kameda), which handles the key exchange process.
-A userland daemon (pluto), which handles all other aspects of the IKE VPN.

The UDP Port Used for IKE Traffic

IKE uses UDP port 500 for traffic from the VPN client to the server.

The IKE Packet Format

UDP port 500 is used for IKE traffic.

IKE uses UDP port 500 for both phase 1 and phase 2 negotiations. VPN clients typically use a random high UDP port for the initial IKE phase 1 negotiation and a random high UDP port for each subsequent phase 2 negotiation.


IKE traffic from a VPN client to server uses UDP port 500.

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