HAProxy 2.6 is now available! As always, the community behind HAProxy made it possible to bring the enhancements in this release. Whether developing new functionality, fixing issues, writing documentation, QA testing, hosting CI environments, or submitting bug reports, members of our community continue to drive the project forward. If you’d like to join the effort, you can find us on GitHub, Slack, Discourse, and the HAProxy mailing list.

In this blog post, you’ll learn how the Proxy Protocol preserves a client’s IP address when that client’s connection passes through a proxy. You will also find resources for how to integrate the protocol into your own proxy or web server software. What is the Proxy Protocol? It is a network protocol for preserving a client’s IP address when the client’s TCP connection passes through a proxy.

HyperText Transfer Protocol (HTTP), the protocol that defines the language browsers use to communicate with web servers, is stateless, meaning that after you make a web request and a server sends back a response, no memory of that interaction remains. To make anything more sophisticated than a static web page work, websites need other ways to remember previous interactions with users.