ISAKMP messages are sent as the payload of UDP messages using UDP port 500. Figure 18-8 shows the format of an ISAKMP message.
Figure 18-8. An ISAKMP message
The ISAKMP message consists of an ISAKMP header and one or more ISAKMP payloads. The ISAKMP payloads contain negotiation information and are encrypted for most ISAKMP messages. The encryption protects the negotiation from being viewed by malicious users who are capturing ISAKMP traffic. The encrypted portions of ISAKMP messages cannot be viewed with Network Monitor. ISAKMP is defined in RFC 2408.
The ISAKMP header is a standard header that is present for all ...