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appnote:chainload_wds [2014/12/22 16:25]
svenx Screenshots from RegEdit and Wireshark
appnote:chainload_wds [2015/11/05 14:11]
svenx TFTP is primarily slow due to latency, not virtualization.
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 ''​HKEY_LOCAL_MACHINE/​SYSTEM/​CurrentControlSet/​Services/​WDSServer/​Providers/​WDSTFTP/​ReadFilter''​ ''​HKEY_LOCAL_MACHINE/​SYSTEM/​CurrentControlSet/​Services/​WDSServer/​Providers/​WDSTFTP/​ReadFilter''​
 that controls which TFTP paths are mapped to the directory containing that controls which TFTP paths are mapped to the directory containing
-the various installation files.+the various installation files defined by the ''​RootFolder''​ registry key in the same location.
  
 {{ :​appnote:​regedit-wdstftp.png?​400|RegEdit WDSTFTP}} {{ :​appnote:​regedit-wdstftp.png?​400|RegEdit WDSTFTP}}
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 Loading the initial WDS network boot program ''​wdsnbp.com''​ can be Loading the initial WDS network boot program ''​wdsnbp.com''​ can be
 done either directly from the iPXE shell or via a menu entry. The only done either directly from the iPXE shell or via a menu entry. The only
-thing that needs to be modified is the DHCP ''​next-server'' ​setting,+thing that needs to be modified is the DHCP ''​next-server'' ​parameter,
 which will let ''​wdsnbp.com''​ know which server to communicate with. which will let ''​wdsnbp.com''​ know which server to communicate with.
 Due to how iPXE handles [[:​settings#​scopes|configuration setting Due to how iPXE handles [[:​settings#​scopes|configuration setting
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     * filename: ''​boot\x64\pxeboot.n12''​.     * filename: ''​boot\x64\pxeboot.n12''​.
     * option 250: ''​0b0101100400000001ff''​     * option 250: ''​0b0101100400000001ff''​
-    * option 252: \Tmp\x86x64{GUID}.bcd+    * option 252: ''​\Tmp\x86x64{GUID}.bcd''​
   - Client: ''​wdsnbp.com''​ requests TFTP ''/​boot\x64\pxeboot.n12''​.   - Client: ''​wdsnbp.com''​ requests TFTP ''/​boot\x64\pxeboot.n12''​.
   - Client: ''​pxeboot''​ requests TFTP ''/​boot\x64\bootmgr.exe''​.   - Client: ''​pxeboot''​ requests TFTP ''/​boot\x64\bootmgr.exe''​.
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   * TFTP error codes from the WDS server.   * TFTP error codes from the WDS server.
   * DHCP options in the client requests and server responses.   * DHCP options in the client requests and server responses.
 +  * The WDS event log in Windows.
  
 ==== TFTP download errors ==== ==== TFTP download errors ====
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 If either ''​wdsnbp.com''​ or ''​pxeboot.n12''​ gets stuck in a request If either ''​wdsnbp.com''​ or ''​pxeboot.n12''​ gets stuck in a request
 loop, it is likely that the initial TFTP download worked, but loop, it is likely that the initial TFTP download worked, but
-subsequent ones are failing. This happens ​because iPXE uses forward+subsequent ones are failing. This can happen ​because iPXE uses forward
 slashes in the TFTP file path, while the WDS boot programs are prone slashes in the TFTP file path, while the WDS boot programs are prone
 to using a mix of forward and backward slashes. to using a mix of forward and backward slashes.
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 HTTP, especially if there is more than a few ms round-trip time HTTP, especially if there is more than a few ms round-trip time
 between the client and server. This results in somewhat long loading between the client and server. This results in somewhat long loading
-times for large WIM images, ​and particularly ​affects virtual machines +times for large WIM images, particularly ​on links with medium ​to 
-that can take ages to download the files.+high latency.
  
-The iPXE author has developed ​[[:​wimboot]],​ a boot loader that takes+A good alternative to the PXE mechanism of WDS is [[:​wimboot]],​ a boot loader that takes
 over the roles of ''​wdsnbp.com''​ and ''​pxeboot.n12''​. It lets you over the roles of ''​wdsnbp.com''​ and ''​pxeboot.n12''​. It lets you
 fetch all the relevant files over HTTP and hand over execution to fetch all the relevant files over HTTP and hand over execution to
appnote/chainload_wds.txt · Last modified: 2015/11/05 14:58 by svenx
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