Administering the NetBIOS Name Cache

You can display and manipulate the entries in a name cache with the nbutil command. You must be root to run nbutil.

There is a maximum of 4096 entries in the NetBIOS name cache.

If you enter: nbutil ? A menu of the options is displayed:

You can use the command line to specify nbutil options.

The following table describes the options that you can specify with the nbutil command.

Option	Description
`-a name -A address` [-l `char`], `[-V]`, `[-D]`, `[-P]`,	Adds an entry to the cache with the specified NetBIOS name and IP address. `-l` sets the last byte for the name; a space (0x20) is the default. `-V` designates a NetBIOS server name and adds two entries into the name cache. `-D` designates a domain controller name and adds two entries into the name cache. `-P` designates a primary domain controller name.
`-c`	Clears the entire cache.
`-d name` `[-l hexbyte]`	Deletes an entry in the cache with the specified NetBIOS name. `-l` sets the last byte for the name; a space (0x20) is the default.
`-g name [-l hexbyte][-v]`	Displays the IP address associated with the specified NetBIOS name. `-l` sets the last byte for the name; a space (0x20) is the default.
`-i`	Displays the status of the cache.
`-n name [-l hexbyte]-v`	Print NetBIOS name table (of the machine that has the NetBIOS name registered).
`-p [-v]`	Prints the contents of the cache. `-v` displays the output in verbose mode.
`-C`	Print current NetBIOS configuration data.
`-L`	Loads entries from the /etc/opt/lmu/netbios/nbhost file into the proxy name cache.
`-N start\|stop`	Starts or stops NetBIOS.
`-S`	Save entries in the proxy name cache to the file /etc/opt/lmu/netbios/nbhost.

A NetBIOS name is 16 bytes long. If you specify a name that is less than 16 bytes, the name is padded with spaces.

Note that a NetBIOS name with a last byte of 0 is considered a different name than a name with a space for the last byte. For example, the following nbutil commands add two different entries to the proxy name cache:

nbutil -a duncan -A 18.13.112.155

nbutil -a duncan -A 18.13.112.155 -l 0

The first command adds the name duncan with a space as the last byte. The second command adds the name duncan with a 0 as the last byte. The -v option displays the entire NetBIOS name, including the pad characters and the last byte, in hexadecimal values. For example, if you enter:

nbutil -p -v

the two entries for the name duncan are displayed:

44 55 4E 43 41 4E 20 20 20 20 20 20 20 20 20 20 (DUNCAN) Addr: 18.13.112.155 44 55 4E 43 41 4E 20 20 20 20 20 20 20 20 20 0 (DUNCAN) Addr: 18.13.112.155

To delete the second entry for duncan, you must specify the -l 0 option. For example, enter:

nbutil -d duncan -l 0

This removes the second entry for duncan. The name duncan, with a space as the last byte, remains in the proxy cache.

Using the nbutil -L option, the node's proxy name cache information can be loaded from the file /etc/opt/lmu/netbios/nbhost. You can edit the nbhost file to include NetBIOS names to IP address mappings following these guidelines:

The file name you edit and use for the name cache must be /etc/opt/lmu/netbios/nbhost.
Each entry must be on a separate line.
Place the NetBIOS name in the first column, followed by the IP address.
Separate the NetBIOS name and IP address by at least one space or tab.
If the last character in the NetBIOS name (16th character) is a non-printing character, enclose the NetBIOS name in quotes and use \nn to specify the non-printing character as hexadecimal. For example: "node78 \03" 15.2.125.234.
The "#" character is used to denote comments in the file.

The heading contents of the nbhost file contain the guidelines and example entries as shown below:

# # This is the NBHOST file used by the HP 9000 RFC NetBIOS Name Cache # # This file contains the mappings of NetBIOS names to IP addresses. # Each entry should be kept on an individual line. # The NetBIOS name should be placed in the first column followed by # the IP address. # The address and the computer name must be separated by at least one # space or tab. # The "#" character is used to denote comments. # # Non-printing characters to be used as the 16th and last character in # the NetBIOS name must be embedded by first enclosing the NetBIOS name # in quotations then using "\nn" notation to specify a hex value for the # non-printing character. # # The RFC NetBIOS name cache supports both unique and group name entries. # All NBHOST file entries are considered unique unless marked as group # name. # The group name marker "#GROUP" must be placed following the netbios # name and IP address. # The IP address and the group name marker must be separated by at least # one space or tab. # # The following are sample entries # # rob_pc 15.1.12.34 # "mac_pc \00" 15.3.32.5 # "node78 \03" 15.2.125.234 # TEST.DOM 15.1.12.34 #GROUP # TEST.DOM 15.3.121.48 #GROUP

Administering the NetBIOS Name Cache

Technical documentation

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