Chx:localonly Patched Jun 2026

chx:localonly is a that tells an intermediate HTTP processor to apply a local policy (logging, rate limiting, transformation) to that specific chunk without propagating the directive downstream. It enables fine‑grained, hop‑by‑hop control over streaming data, useful in complex proxy chains, debugging, and traffic shaping. Implementers must ensure it’s properly stripped to avoid leaking internal state.

While not a standard global constant across all software, the syntax suggests a setting found in (like Proxifier or Charles Proxy), firewall rules , or application server configurations . chx:localonly

# iptables equivalent logic iptables -A INPUT -p tcp --dport 9000 ! -s 127.0.0.1 -j DROP chx:localonly is a that tells an intermediate HTTP

In non‑HTTP/1.1 contexts, chx:localonly might appear in (e.g., HAProxy’s http-response set-header with a local-only flag). While not a standard global constant across all

chx is shorthand for or "chunk extension" in HTTP. In the HTTP/1.1 specification (RFC 7230), chunked encoding allows a response body to be sent in pieces. Each chunk can have chunk extensions — optional metadata after the chunk size.

A typical chunk looks like: