Which IP protocol defines GRE packets?
- 47
- 51
- 17
- 50
Explanation: Generic Routing Encapsulation (GRE) is a tunneling protocol that provides a path for transporting packets over a public network by encapsulating them inside a transport protocol. One of the primary characteristics of this protocol is that IP protocol 47 defines GRE packets.
GRE is designed to encapsulate arbitrary types of network layer packets inside other network layer packets, which allows routing information to pass between connected networks. While it adds a 20-byte IP delivery header and a 4-byte GRE header to hide existing packet headers, the sources note that GRE is stateless and does not include strong security or encryption mechanisms by itself.
Related exam: Modules 17 – 20: Checkpoint Exam: Virtualization and Network Services Answers (CCNP ENCOR v9)
