Other Useful Protocols

To transfer large files between network devices.

To establish secure, encrypted tunnels for private communication.

To check the reachability and operational status of network devices.

To assign IP addresses dynamically to new devices on a network.

GRE provides built-in encryption, while VPNs require external encryption protocols.

VPNs are used for local networks, while GRE is for wide area networks.

GRE encapsulates traffic within IP packets, whereas VPNs do not.

VPNs encrypt data traversing a public network, while GRE does not provide built-in encryption.

Layer 2; provides MAC address filtering and VLAN tagging.

Layer 3; offers authentication, encryption, integrity, and anti-replay.

Layer 4; ensures reliable data transfer and flow control.

Layer 7; manages application-level protocols and data formatting.

TCP/80

UDP/500

TCP/443

UDP/161

Transport mode

Tunnel mode

Authentication Header (AH) mode

Encapsulation Security Payload (ESP) mode