RFC 3143 (rfc3143) - Page 1 of 32
Known HTTP Proxy/Caching Problems
Alternative Format: Original Text Document
Network Working Group I. Cooper
Request for Comments: 3143 Equinix, Inc.
Category: Informational J. Dilley
Akamai Technologies, Inc.
June 2001
Known HTTP Proxy/Caching Problems
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This document catalogs a number of known problems with World Wide Web
(WWW) (caching) proxies and cache servers. The goal of the document
is to provide a discussion of the problems and proposed workarounds,
and ultimately to improve conditions by illustrating problems. The
construction of this document is a joint effort of the Web caching
community.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Problem Template . . . . . . . . . . . . . . . . . . . . . . 2
2. Known Problems . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Known Specification Problems . . . . . . . . . . . . . . . . 5
2.1.1 Vary header is underspecified and/or misleading . . . . . . 5
2.1.2 Client Chaining Loses Valuable Length Meta-Data . . . . . . 9
2.2 Known Architectural Problems . . . . . . . . . . . . . . . . 10
2.2.1 Interception proxies break client cache directives . . . . . 10
2.2.2 Interception proxies prevent introduction of new HTTP
methods . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2.3 Interception proxies break IP address-based authentication . 12
2.2.4 Caching proxy peer selection in heterogeneous networks . . . 13
2.2.5 ICP Performance . . . . . . . . . . . . . . . . . . . . . . 15
2.2.6 Caching proxy meshes can break HTTP serialization of content 16
2.3 Known Implementation Problems . . . . . . . . . . . . . . . 17
2.3.1 User agent/proxy failover . . . . . . . . . . . . . . . . . 17
2.3.2 Some servers send bad Content-Length headers for files that
contain CR . . . . . . . . . . . . . . . . . . . . . . . 18
Cooper & Dilley Informational
