6 Appendix A: Product Behavior

The information in this specification is applicable to the following Microsoft products or supplemental software. References to product versions include updates to those products.

The terms "earlier" and "later", when used with a product version, refer to either all preceding versions or all subsequent versions, respectively. The term "through" refers to the inclusive range of versions. Applicable Microsoft products are listed chronologically in this section.

Windows Client

• Windows NT operating system

• Windows 2000 Professional operating system

• Windows XP operating system

• Windows Vista operating system

• Windows 7 operating system

• Windows 8 operating system

• Windows 8.1 operating system

• Windows 10 operating system

• Windows 11 operating system

Windows Server

• Windows NT

• Windows 2000 Server operating system

• Windows Server 2003 operating system

• Windows Server 2008 operating system

• Windows Server 2008 R2 operating system

• Windows Server 2012 operating system

• Windows Server 2012 R2 operating system

• Windows Server 2016 operating system

• Windows Server operating system

• Windows Server 2019 operating system

• Windows Server 2022 operating system

• Windows Server 2025 operating system

Exceptions, if any, are noted in this section. If an update version, service pack or Knowledge Base (KB) number appears with a product name, the behavior changed in that update. The new behavior also applies to subsequent updates unless otherwise specified. If a product edition appears with the product version, behavior is different in that product edition.

Unless otherwise specified, any statement of optional behavior in this specification that is prescribed using the terms "SHOULD" or "SHOULD NOT" implies product behavior in accordance with the SHOULD or SHOULD NOT prescription. Unless otherwise specified, the term "MAY" implies that the product does not follow the prescription.

<1> Section 2.1: Windows Media Player 6, Windows Media Format 7.0 SDK, Windows Media Format 7.1 SDK, and Windows Media Player for Windows XP support Basic authentication (as specified in [RFC2617] and [MS-NLMP]). Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later support [MS-NLMP], Digest (as specified in [RFC2617]), and Negotiate (as specified in [RFC4559]) authentication. Basic authentication is only supported when challenged by a proxy server. Windows Media Services on Windows NT Server 4.0 operating system and on Windows 2000 Server support Basic and [MS-NLMP] authentication. Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 support [MS-NLMP], Digest, and Negotiate authentication. Authentication protocols on the server are disabled by default and can be selectively enabled by the server administrator.

<2> Section 2.2.1.1: This header is not supported by Windows Media Player 6, or by Windows Media Services on Windows NT Server 4.0 and on Windows 2000 Server.

<3> Section 2.2.1.1.4: Windows will not specify this directive without a third party plugin.

<4> Section 2.2.1.1.5: Windows will not specify this directive without a third party plugin.

<5> Section 2.2.1.1.6: Windows will not specify this directive without a third party plugin.

<6> Section 2.2.1.1.7: Windows will not specify this directive without a third party plugin.

<7> Section 2.2.1.1.9: This directive is only supported by Windows Media Services on Windows Server 2003, Windows Server 2008 and Windows Server 2008 R2.

<8> Section 2.2.1.1.10: Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, and Windows Vista only support the "remote-log" event.

<9> Section 2.2.1.1.11: This directive is only supported by Windows Media Services on Windows Server 2003, Windows Server 2008 and Windows Server 2008 R2.

<10> Section 2.2.1.1.12: This directive is only supported by Windows Media Services on Windows Server 2003, Windows Server 2008 and Windows Server 2008 R2.

<11> Section 2.2.1.2: Windows Media Services on Windows NT 4.0 operating system and Windows 2000 Server only sends the "application/octet-stream" content-type. Also, Windows Media Player 6 only sends the "text/plain" content-type in its POST requests.

<12> Section 2.2.1.2.4: This content-type is only supported by Windows Media Services on Windows Server 2003, Windows Server 2008 and Windows Server 2008 R2.

<13> Section 2.2.1.2.5: This content-type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later; and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<14> Section 2.2.1.2.6: This content-type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later; and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<15> Section 2.2.1.2.7: This content-type is only sent by Windows Media Player 6, Windows Media Format 7.0 SDK, Windows Media Format 7.1 SDK, and by Windows Media Player for Windows XP, and by Windows Media Services on Windows NT 4.0 and Windows 2000 Server.

<16> Section 2.2.1.4: When Windows Media Services is acting in the server role, it will typically respond to errors with "400 Bad Request" or a similar HTTP error code. Implementations of the client role on Windows (listed in the introduction to this section) will typically close the connection to the server and display an error message to the user.

<17> Section 2.2.1.4.1: This token is supported by Windows Media Player for Windows XP, Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. The token is also sent by Windows Media Format 7.0 SDK and by Windows Media Format 7.1 SDK. However, those products do not properly process the token in a response; thus, the requirement to not send the token to clients that have a version number that is less than 8.

<18> Section 2.2.1.4.2: This token is supported by Windows Media Player for Windows XP, Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. The token is also sent by Windows Media Format 7.0 SDK and by Windows Media Format 7.1 SDK, but those products do not properly process the token in a response; thus, the requirement to not send the token to clients that have a version number that is less than 8.

<19> Section 2.2.1.4.3: This token is supported by Windows Media Services on the Windows Server 2003, Windows Server 2008 and Windows Server 2008 R2.

<20> Section 2.2.1.4.4: This token is supported by Windows Media Services on Windows Server 2003, Windows Server 2008 and Windows Server 2008 R2.

<21> Section 2.2.1.4.6: This token is supported by Windows Media Player for Windows XP, Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<22> Section 2.2.1.4.8.2: This token is not supported by Windows.

<23> Section 2.2.1.4.8.4: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<24> Section 2.2.1.4.8.6: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<25> Section 2.2.1.4.8.7: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<26> Section 2.2.1.4.9: This token is supported by Windows Media Format 7.0 SDK, Windows Media Format 7.1 SDK, Windows Media Player for Windows XP, Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. When supported, the value of the token is set to the link bandwidth if it has been configured by the user or the link bandwidth if it was successfully determined through a packet-pair experiment. If the link bandwidth is unknown, the token is not transmitted. Windows Media Services on Windows Server 2003 uses the value of the token in determining which streams are selected when it switches to the next entry (if any) in a server-side playlist.

<27> Section 2.2.1.4.11: This token is not ignored by Windows Media Services on Windows NT 4.0 and Windows 2000 operating system.

<28> Section 2.2.1.4.14: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<29> Section 2.2.1.4.15: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<30> Section 2.2.1.4.16: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<31> Section 2.2.1.4.17: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<32> Section 2.2.1.4.18: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<33> Section 2.2.1.4.19: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<34> Section 2.2.1.4.20: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<35> Section 2.2.1.4.23: The first Play request sent by Windows Media Player 6 specifies a value for this token that is 2. For other GET requests sent by Windows Media Player 6, the token is either omitted or has a value that is greater than 2. The first Play request sent by Windows Media Services on Windows NT 4.0 and Windows 2000 specifies a value for this token that is either 2 or 3. For other GET requests sent by Windows Media Services on Windows NT 4.0 and Windows 2000, the token is either omitted or has a value that is greater than 3.

<36> Section 2.2.1.4.24: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 can respond to a request that specifies this token with a speed token that specifies a value that is less than what the client specified, but it will never be less than 1 if the client specified a value greater than 1.

<37> Section 2.2.1.4.30: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<38> Section 2.2.1.4.31: This token is supported by Windows Media Player 6 and Windows Media Services on Windows NT 4.0 and Windows 2000. The Versions of Windows Media Services that support this token do not send it, unless configured to do so.

<39> Section 2.2.1.4.32: This token is supported by Windows Media Player 6 and Windows Media Services on Windows NT 4.0 and Windows 2000. The versions of Windows Media Services that support this token do not send it, unless configured to do so.

<40> Section 2.2.1.4.34: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. The client products that support this token will send a request with the token if the connection has been idle for the amount that the server specified in the timeout token. Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 will reset its idle timeout timer for the specified session whenever it receives a request with the xKeepAliveInPause token.

<41> Section 2.2.1.4.35: The pipelined mode of the protocol, and hence also this token, is only supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<42> Section 2.2.1.4.38: The pipelined mode of the protocol, and hence also this token, is only supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<43> Section 2.2.1.5: In Windows, the server assigns the values of the server-token according to the following table.

<44> Section 2.2.1.7: This header is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<45> Section 2.2.1.7.5: The X-StartupProfile (section 2.2.1.12) header is supported by Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003 with SP1, Windows Server 2008, and Windows Server 2008 R2.

<46> Section 2.2.1.8: In Windows, the client assigns the values of the client-token according to the following table.

<47> Section 2.2.1.9: This header is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. Windows Media Player 6, Windows Media Format 7.0 SDK, Windows Media Format 7.1 SDK, and Windows Media Player for Windows XP support Basic (as specified in [RFC2617]) and MS-NLMP authentication (as specified in [MS-NLMP]). Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later support MS-NLMP (as specified in [MS-NLMP]), Digest (as specified in [RFC2617]), and Negotiate authentication (as specified in [RFC4559]). Basic authentication is only supported when challenged by a proxy server. Windows Media Services on Windows NT 4.0 and on Windows 2000 Server supports Basic and MS-NLMP authentication. Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 supports MS-NLMP, Digest, and Negotiate authentication. Authentication protocols on the server are disabled by default and can be selectively enabled by the server administrator.

<48> Section 2.2.1.10: This header is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. Windows Media Player 6, Windows Media Format 7.0 SDK, Windows Media Format 7.1 SDK, and Windows Media Player for Windows XP support Basic (as specified in [RFC2617]) and MS-NLMP authentication (as specified in [MS-NLMP]). Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later support Basic, MS-NLMP, Digest (as specified in [RFC2617]), and Negotiate authentication (as specified in [RFC4559]). Windows Media Services on Windows NT 4.0 and on Windows 2000 Server supports Basic and MS-NLMP authentication. Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 supports MS-NLMP, Digest, and Negotiate authentication. Authentication protocols on the server are disabled by default and can be selectively enabled by the server administrator.

<49> Section 2.2.1.12: This header is supported by Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<50> Section 2.2.2.2: This request type is supported by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<51> Section 2.2.2.3: This request type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<52> Section 2.2.2.7: This request type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<53> Section 2.2.2.9: This request type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<54> Section 2.2.2.10: This request type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<55> Section 2.2.3.1: Implementations on Windows (listed in the introduction to this section) typically close the connection to the server and display an error message to the user if a packet is received with a field set to an invalid value.

<56> Section 2.2.3.1.1: This field is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. Windows Media Services sets this field to 1 on any packets that are transmitted faster than real time as the result of the client having specified the AccelBW (section 2.2.1.4.1) token on the pragma header.

<57> Section 2.2.3.7: This packet type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<58> Section 2.2.3.8: This packet type is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2.

<59> Section 2.2.5: Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, and Windows Vista support only the "remote-log" event.

<60> Section 3.1.5.1: The com.microsoft.wm.startupprofile (section 2.2.1.7.5) token is only specified by Windows Media Format 9.5 SDK, Windows Vista and later. Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, and Windows Vista only specify the com.microsoft.wm.predstrm (section 2.2.1.7.2) token when the most recent Play (section 2.2.2.6) or PlayNextEntry (section 2.2.2.7) request did not include the speed token with a value other than 1 on a Pragma (section 2.2.1.4) header.

<61> Section 3.1.5.1: Whether the same GUID is used for all sessions or changed between different sessions is determined by how the user has configured Windows Media Player and/or the Windows Media Format SDK.

<62> Section 3.1.5.1: Only Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 supports sending a Pragma (section 2.2.1.4) header with the proxy-client-agent (section 2.2.1.4.21) token or a X-Proxy-Client-Verb (section 2.2.1.11) header.

<63> Section 3.1.5.1: The Cookie (section 2.2.1.3) header can be sent by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, and Windows Vista.

<64> Section 3.1.5.3: Windows Media Player 6, Windows Media Format 7.0 SDK, Windows Media Format 7.1 SDK, and Windows Media Player for Windows XP support Basic (as specified in [RFC2617]) and NTLM (as specified in [NTLM]) authentication. Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later support NTLM, Digest (as specified in [RFC2617]), and Negotiate (as specified in [RFC4559]) authentication. Basic authentication is only supported when challenged by a proxy server. Windows Media Services on Windows NT 4.0 and on Web Services for Management (WS-Management) Windows 2000 Server supports Basic and NTLM authentication. Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 supports NTLM, Digest, and Negotiate authentication.

<65> Section 3.1.5.3: This token is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and by Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2. Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 will disconnect a client that has been idle, but the actual time-out used can be greater (but never smaller) than the time-out specified by the token.

<66> Section 3.1.5.3: Only Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later support caching of content, and thus only those product versions will adhere to the directives on the Cache-Control header.

<67> Section 3.1.5.3: Windows Media Player 6 will use the URL specified in the value of the version-info token to download an update but only if the version number specified by the version-info token is greater than the current version number of Windows Media Player.

<68> Section 3.1.5.3: The Set-Cookie (section 2.2.1.6) header is supported by Windows Media Format 9 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later.

<69> Section 3.2.5.1: Windows Media Services will respond to the request with HTTP status code 200 and the message response of the request will contain an ASX file (as described in [MSDN-ASX]) that contains the same URL that the client provided in the request. Because ASX files are understood by Windows Media Player, it is expected that the web client will invoke Windows Media Player to parse the ASX file.

<70> Section 3.2.5.2: The com.microsoft.wm.startupprofile (section 2.2.1.7.5) token is only specified by Windows Media Services on Windows Server 2003 with SP1, Windows Server 2008 and Windows Server 2008 R2.

<71> Section 3.2.5.4: Windows Media Services on Windows NT 4.0 and Windows 2000 Server sends the "application/octet-stream" content-type and does not send the application/vnd.ms.wms-hdr.asfv1 content-type.

<72> Section 3.2.5.6: The AccelDuration specified by Windows Media Services on Windows Server 2003, Windows Server 2008 and Windows Server 2008 R2 could be larger than the client-specified value.

<73> Section 3.2.5.6: Windows Media Services on Windows NT 4.0 and Windows 2000 Server sends the "application/octet-stream" content-type and does not send the application/x-mms-framed content-type.

<74> Section 3.2.5.11: Windows Media Services on Windows NT 4.0, Windows Media Services on Windows 2000 Server, Windows Media Player 6, Windows Media Format 7.0 SDK, Windows Media Format 7.1 SDK, Windows Media Player for Windows XP, Windows Media Format 9.0 Series SDK, Windows Media Format 9.5 SDK, Windows Vista and later, and Windows Media Services on Windows Server 2003, Windows Server 2008, and Windows Server 2008 R2 will not fail a logging request for invalid or illegal syntax.