DOCUMENT:Q101927  28-JUL-1993  [W_NT]
TITLE   :INF: The LHMOSTS File for TCP/IP in Windows NT
PRODUCT :Windows NT
PROD/VER:3.10
OPER/SYS:WINDOWS
KEYWORDS:

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The information in this article applies to:
 
 - Microsoft Windows NT operating system, version 3.1
 - Microsoft Windows NT Advanced Server, version 3.1
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The LMHOSTS file is a local text file that maps IP addresses to
NetBIOS names of remote servers with which you want to communicate
over the TCP/IP protocol.
 
Windows NT recognizes names instead of IP addresses for network
requests and a name discovery process is used to correctly route
network requests with TCP/IP. Because the name discovery process is
generally not routed by an IP router, the LMHOSTS file allows Windows
NT computers to communicate using TCP/IP across a subnet bridged by an
IP router.
 
Under TCP/IP alone, NBT (NetBIOS over TCP/IP) checks this list in
memory before doing a b-node name discovery. For example, a reference
to \\Eric would be translated to reference the actual IP address of
135.25.25.14 (this is a fictional address).
 
A sample LMHOSTS file:
----------------------
142.25.125.15 Joe #PRE
129.102.12.10 Paul #PRE
148.107.16.45 James
135.25.25.14 Eric #PRE
133.120.26.225 John
192.36.14.250 Ed #PRE
221.250.05.126 Mackey
 
Note:  All addresses are fictional.
 
When Windows NT loads, it reads the first 100 entries, by default, in
the LMHOSTS file marked with #PRE. You can increase the number of #PRE
entries that will load into memory at logon by adding the MaxPreLoads
entry in the registry. This entry should be added to the
Hkey_Local_Machine\CurrentControlSet\Services\NBT\Parameters section
of the registry.
 
The maximum number allowed for MaxPreLoads depends on the performance
of the system. Some computers are able to parse or search through more
entries in the LMHOSTS file than others. Based on system performance,
Windows NT usually searches through about 1000 entries before timing
out (15 seconds).
 
Additional reference words: 3.10
KBCategory:
KBSubcategory: tpip

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Copyright Microsoft Corporation 1993.