Introduction to IPsec VPN on Reyee EG

1. Overview
IP Security (IPsec) is a Layer 3 tunnel encryption protocol defined by the IETF. IPsec is used to provide end-to-end encryption and verification services in the network to provide high quality and interoperability for data transmission over the network and ensure transmission security by using cryptographic algorithms. The communicating parties obtain the following security services at the IP layer through encryption and data source authentication:

• Confidentiality: The IPsec sender encrypts packets before transmittingthe packets over the network.
• Data integrity: The IPsec receiver authenticates packets received fromthe sender to ensure that data is not tampered with during the transmission.
• Data authentication: The IPsec receiver authenticates whether the senderof IPsec packets is valid.
• Anti-replay: The IPsec receiver detects and denies expired or repeatedpackets.
  

The IPsec protocol is widely used for communication between the HQ and branches of an organization. Currently, the device can be deployed as the IPsec server or client. A secure tunnel is established between the HQ and each branch based on the IPsec protocol to ensure the confidentiality of data transmission and improve network security.
2. IPsec security policies Introduction

IPsec security policies define security proposals (equivalent to SA) for data flows. You can configure matching security policies on both parties engaged in the communication to establish IPsec tunnels between the IPsec client and the IPsec server, protecting the communication data. An IPsec security policy consists of two parts: basic settings and advanced settings. Advanced settings are optional and include the specific IKE policy and connection policy. You can keep the default settings unless otherwise specified.