Legacy Opt-Out Cookie Strings That Are Supported by Internet Explorer 6

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Article ID: 304531 - View products that this article applies to.
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This article describes the special provision that is implemented by Internet Explorer 6 for legacy opt-out cookies. Internet Explorer 6 defines legacy cookies as cookies that were on your computer prior to installing Internet Explorer 6.


Internet Explorer 6 makes a special provision for opt-out legacy cookies. Often, when you opt out of an online service, an opt-out cookie is used by the Web service to facilitate this choice. The success of this transaction sometimes relies on the ability of the browser to send this cookie in both first-party and third-party contexts. However, with Internet Explorer 6, legacy cookies are leashed and are not sent in the third-party context. In response to this problem, Internet Explorer 6 does not leash cookies that contain any of the following name/value pairs:
  • AA002=optout
  • id=OPT_OUT
  • CyberGlobalAnonymous=optout
Note that these name/value strings are case sensitive and space sensitive.

Web sites should upgrade their opt-out cookies to use this syntax to ensure that legacy opt-out cookies are effective in Internet Explorer 6. After Internet Explorer 6 is installed, new opt-out cookies are handled just like any other non-legacy cookie. This special provision does not affect non-legacy cookies (cookies that are set after Internet Explorer 6 is installed).

For developer information about the Privacy implementation in Internet Explorer 6, visit the following Microsoft Web site:


Article ID: 304531 - Last Review: February 28, 2014 - Revision: 3.4
  • Microsoft Internet Explorer 6.0, when used with:
    • Microsoft Windows XP Home Edition
    • Microsoft Windows XP Professional
    • Microsoft Windows XP Media Center Edition
    • Microsoft Windows XP Tablet PC Edition
    • Microsoft Windows XP Professional x64 Edition
    • Microsoft Windows 2000 Advanced Server
    • Microsoft Windows 2000 Datacenter Server
    • Microsoft Windows 2000 Professional Edition
    • Microsoft Windows 2000 Server
    • Microsoft Windows NT Server 4.0 Standard Edition
    • Microsoft Windows NT Server 4.0, Terminal Server Edition
    • Microsoft Windows NT Workstation 4.0 Developer Edition
    • Microsoft Windows Millennium Edition
    • Microsoft Windows 98 Second Edition
    • Microsoft Windows 98 Standard Edition
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