The ESP header is located after the IP header and before the transport mode protocol (UDP or TCP) or before an encapsulated IP header when using tunneling.

ESP报头位于IP报头之后，传输模式(UDP或者TCP)之前，或者当使用隧道时是在封装的IP报头之前。

youdao

The Encapsulated Security Payload (ESP) header has the ability to provide encryption as well as packet authentication.

封装的安全有效载荷(esp)报头有能力提供加密和包认证功能。

youdao