> For the complete documentation index, see [llms.txt](https://docs.console.zenlayer.com/glossary/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.console.zenlayer.com/glossary/i/ipsec.md). # IPSec IPSec (Internet Protocol Security) is a protocol used for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet in a communication session. IPSec can provide confidentiality, integrity, and authentication for IP datagrams by using cryptographic techniques. It operates at the network layer, and can be used to secure communication between two network endpoints, such as between two routers, two hosts, or between a remote access client and a VPN gateway. IPSec can be used in tunnel mode or transport mode, and supports various encryption and authentication algorithms. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.console.zenlayer.com/glossary/i/ipsec.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.