Apache Traffic Serverâ„¢ software is a fast, scalable and extensible HTTP/1.1 compliant caching proxy server. Formerly a commercial product, Yahoo! donated it to the Apache Foundation, and it is now an Apache TLP. Here's a Traffic Server overview.

Important security announcements:

All versions of Traffic Server prior to v5.0.1 (or v4.2.1.1) have a vulnerability related to the synthetic health checks as used by traffic_cop. We urge everyone to upgrade to the latest releases, either v4.2.1.1 or v5.1.2. See CVE-2014-3525 for some details.

Traffic Server 5.1.0 has a security issue that can lead to acting as an open relay under specific circumstances. Traffic Server 5.1.1 has a security issue which makes it vulnerable to denial of service attacks. We urge all deployments of 5.1.0 and 5.1.1 to upgrade to 5.1.2. See CVE-2014-3624 and TS-2677 for more detail.

  • Caching

    Improve your response time, while reducing server load and bandwidth needs by caching and reusing frequently-requested web pages, images, and web service calls.

  • Proxying

    Easily add keep-alive, filter or anonymize content requests, or add load balancing by adding a proxy layer.

  • Fast

    Scales well on modern SMP hardware, handling 10s of thousands of requests per second.

  • Extensible

    APIs to write your own plug-ins to do anything from modifying HTTP headers to handling ESI requests to writing your own cache algorithm.

  • Proven

    Handling over 400TB a day at Yahoo! both as forward and reverse proxies, Apache Traffic Server is battle hardened. Also visit our Customers page (see link above) for some of our corporate users and supporters.

  • Having trouble with builds, configurations or are you getting errors you don't understand? Subscribe to our Users Mailing List or join our #traffic-server channel on irc.freenode.net to get help!

  • Can't get your plugin to work? Get help from developers or start a discussion on our dev discussion list.

  • Report or confirm bugs or try out the latest patches from our Bug Tracker

  • Learn here how to ask good questions, create useful bug reports and how to apply patches.

  • Subscribe and help out on the users Mailing List or simply share your usecase or experience. For (hopefully) speedier responses check out our IRC channel #traffic-server on irc.freenode.net.

  • Impress developers or help others by participating on our dev discussion list or follow the latest development on our commits list.

  • Report issues or bring patches to our Bug Tracker

  • Visit our wiki to see a list of Projects we are currently working on.

  • Learn here how to create patches to the code or the documentation and how to debug Apache Traffic Server..

  • Or just fix a random bug!

  • A low entrance barrier is helping us clean up our code: Fix clang build warnings.

  • January 14, 2015: We are pleased to announce the next quarterly release, v5.2.0. It's as usual available from the Downloads page.
  • December 16, 2014: 5.1.2 is a security update for 5.1.1. We urge everyone to upgrade from 5.1.0 or 5.1.1 to 5.1.2 as soon as possible.
  • October 31, 2014: 5.1.1 is a security update for 5.1.0. We urge everyone to upgrade from 5.1.0 to 5.1.1 as soon as possible. See CVE-2014-3566 and CVE-2014-3624.
  • September 18, 2014: We are pleased to announce the relase of our quarterly minor release, v5.1.0. It's available from our Downloads page.
  • September 08, 2014: The old, legacy release of ATS, v3.2.x, is no longer supported. We have removed it from the download site, but it is available via the archives. We urge everyone to migrate to v4.2.x or 5.x as soon as possible.
  • September 04, 2014: A bug-fix release for v4.2 is now available. Fetch the latest v4.2.2 tarballs from the Downloads section. This is our LTS branch for 4.x.
  • July 23, 2014: A security flaw in handling of healthchecks was discovered, affecting all versions of ATS. We urge everyone to upgrade to v4.2.1.1 or v5.0.1 immediately. See CVE-2014-3525 for details.
  • June 17, 2014: We are extremely pleased to announce the release of our latest major release, v5.0.0! This has been a year in the making, and includes a number of new features and bug fixes.
  • April 29, 2014: A bug-fix release for v4.2 is now available. Fetch the latest v4.2.1 tarballs from the Downloads section. This is our LTS branch for 4.x.
  • March 19, 2014: A minor release for v4.x is now available. Fetch the latest v4.2.0 builds from the Downloads section. This is our LTS branch for 4.x.
  • Archived News