qemu-options: Improve description for -smb option
Add #PRE and #NOFNR flags to LMHOSTS example line. Include information about LMHOSTS path on Windows 3.x. Windows NT 3.1 requires #NOFNR flag for successful hostname resolving as described in MS article Q103765 because qemu/smbd does not respond to netbios name verification queries. #PRE is suggested in that article too and decrease delay on Windows 3.x for the first connection. Signed-off-by: Pali Rohár <pali@kernel.org> [PMM: Expand documentation to note what these flags do, and clarify Windows LMHOSTS paths for different Windows versions, based on discussion in patch review, fix existing grammar nit] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Pali Rohár committed
May 5, 2026 at 09:25 UTC
aac1599820a127a8869bf86da26c2a1cc05ec260
1 file changed
+14
-5
qemu-options.hx
+14
-5
@@ -3415,7 +3415,7 @@ SRST
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``smb=dir[,smbserver=addr]``
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When using the user mode network stack, activate a built-in SMB
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- server so that Windows OSes can access to the host files in
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+ server so that Windows OSes can access the host files in
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``dir`` transparently. The IP address of the SMB server can be
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set to addr. By default the 4th IP in the guest network is used,
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i.e. x.x.x.4.
@@ -3424,11 +3424,20 @@ SRST
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::
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- 10.0.2.4 smbserver
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+ 10.0.2.4 smbserver #PRE #NOFNR
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- must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows
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- 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows
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- NT/2000).
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+ must be added in the ``LMHOSTS`` file. In this line, ``#PRE``
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+ requests pre-caching of the mapping, which speeds up the initial
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+ connection on some Windows versions. ``#NOFNR`` is necessary for
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+ Windows NT 3.1 to tell it not to send NBNS query packets that
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+ QEMU does not handle, and is harmlessly ignored on other versions.
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+
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+ The ``LMHOSTS`` file may be in different locations depending on
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+ the Windows version:
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+
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+ - ``C:\WINDOWS\LMHOSTS`` for Windows 3x/9x/Me
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+ - ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` for Windows NT/2000
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+ - ``C:\WINDOWS\SYSTEM32\DRIVERS\ETC\LMHOSTS`` for Windows XP and newer
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Then ``dir`` can be accessed in ``\\smbserver\qemu``.
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