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<P><SPAN LANG="nl"><FONT SIZE=2 FACE="Arial">Dear iPXE developers,</FONT></SPAN>
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<P><SPAN LANG="nl"><FONT SIZE=2 FACE="Arial">I'm having the following problem with iPXE; I'm using the bootable ISO that I burned to a CD-ROM.</FONT></SPAN>
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<P><SPAN LANG="nl"><FONT SIZE=2 FACE="Arial">I'm booting WinPE over PXE. This works when I'm using a DHCP server on a local subnet (on which I can set the correct scope options), but due to security policies I cannot set DHCP scope options on the rest of the network. So the objective is to boot iPXE from CD-ROM or USB-key with an embedded script that simply executes:</FONT></SPAN></P>
<P><SPAN LANG="nl"> <FONT SIZE=2 FACE="Arial">dhcp</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">set next-server x.x.x.x</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">imgfetch /Boot/pxeboot.n12</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">boot pxeboot.n12</FONT></SPAN>
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<P><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">I tested this and it works well. It doesn't work anymore though when I increase the TFTP block size within the BCD config (so Microsoft's bootmgr.exe will request bigger chunks of data from the TFTP-server).</FONT></SPAN></P>
<P><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">Our TFTP-server must be reached over a WAN (cross-country), so TFTP-throughput is very slow (inherent of the protocol, since it's UDP and every packet needs to be acknowledged). On all of our PC's on the local subnet (using DHCP scope options and the BOOT ROM of the NIC, so not iPXE) it works well when I increase tftpblocksize to 8K and download time of a standard WinPE image drops from 10 minutes to 1,5 minute; which is great. But iPXE is unable to handle this kind of TFTP-traffic.</FONT></SPAN></P>
<P><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">Here's the script that I use to create the BCD config:</FONT></SPAN>
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<P><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">set BCD-File=C:\TFTP-ROOT\Boot\BCD</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">del %BCD-File%</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /createstore %BCD-File%</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /create {ramdiskoptions}</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set {ramdiskoptions} ramdisksdidevice boot</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set {ramdiskoptions} ramdisksdipath \boot\boot.sdi</FONT></SPAN>
<BR><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">---> Bcdedit /store %BCD-File% /set {ramdiskoptions} ramdisktftpblocksize 1432</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set {ramdiskoptions} ramdisktftpwindowsize 2</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Set guid={10000000-1000-1000-1000-100000000000}</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /create %guid% /d "WinPE PXE-boot image" /application osloader</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set %guid% systemroot \Windows</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set %guid% detecthal Yes</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set %guid% winpe Yes</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set %guid% osdevice ramdisk=[boot]\Boot\winpe_x86.wim,{ramdiskoptions}</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set %guid% device ramdisk=[boot]\Boot\winpe_x86.wim,{ramdiskoptions}</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /create {bootmgr} /d "Lite Touch Installation" </FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set {bootmgr} timeout 1</FONT></SPAN>
<BR><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set {bootmgr} displayorder %guid%</FONT></SPAN>
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<P><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">This works, but is very slow. So I replace line 7 with:</FONT></SPAN>
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<P><SPAN LANG="fr-be"> <FONT SIZE=2 FACE="Arial">Bcdedit /store %BCD-File% /set {ramdiskoptions} ramdisktftpblocksize 8192</FONT></SPAN>
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<P><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">Now it still works on pc's using the internal NIC's PXE-boot code (and it's much faster), but it doesn't work anymore with iPXE.</FONT></SPAN></P>
<P><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">My guess is that iPXE cannot handle TFTP-responses that are spread over multiple ethernet frames. 1432 bytes works well because with overhead it's lower than the MTU (1500 bytes). But when the TFTP-server sends 2 or more UDP packets (to send a bigger block of data, requiring less acknowledgements), these somehow get lost.</FONT></SPAN></P>
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<P><SPAN LANG="fr-be"><FONT SIZE=2 FACE="Arial">Any ideas? Thanks a lot in advance.</FONT></SPAN>
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<P><B><SPAN LANG="nl"><FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">Best regards,</FONT></SPAN></B>
<BR><B><SPAN LANG="nl"><FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">Bien à Vous,</FONT></SPAN></B>
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<P><B><SPAN LANG="nl"> <FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">Tom Lauwers</FONT></SPAN></B><SPAN LANG="nl"></SPAN>
<BR><SPAN LANG="it"> <FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">DIGIT A.2-002 Desktop, Peripherals & Mobile Solutions</FONT></SPAN>
<BR><SPAN LANG="it"> <FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">Siemens</FONT></SPAN>
<BR><SPAN LANG="fr"> <I> <FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">Office: B-28 03/030</FONT></I></SPAN>
<BR><SPAN LANG="fr"> <I> <FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">Tel.</FONT></I></SPAN><I><SPAN LANG="it"><FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS"> (+32-2)[29]51649 -</FONT></SPAN><SPAN LANG="en-us"> <FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">Fax. (+32-2)[29]50164</FONT></SPAN></I><SPAN LANG="en-us"><BR>
</SPAN><SPAN LANG="fr"> </SPAN><SPAN LANG="fr"><I> <FONT COLOR="#000080" SIZE=2 FACE="Arial Unicode MS">E-mail: tom.lauwers@ext.ec.europa.eu</FONT></I></SPAN><SPAN LANG="en-us"><BR>
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