dhcpdb - DHCP database manager
/usr/sbin/dhcpdb [ -a [ -r] ] | [ -d ] | [ -u ] | [ -p ] [ -X ]
[ -C Client_id ] [ -M Mac_address ] [ -I IP_address ]
[ -H hostname ] [ -T lease_in_seconds ] [ -f dhcp_database ]
/usr/sbin/dhcpdb [ -D ] | [ -L ] [ -X ] [ -f dhcp_database ]
dhcpdb is a database manager for the NDBM database used by the DHCP
server to store address leases. It provides a command line interface to
add, delete, update, or print the DHCP database.
The tool can be used either in entry mode to manipulate individual
entries or in file mode. In file mode the entire contents of the database
can be dumped to a file or loaded from a file.
COMMAND LINE OPTIONS
In the entry mode options can be used to add (replace), delete, update a
lease, or print an entry using a key. The key can be either a client
identifier, MAC (interface) address, IP address, or a hostname.
-a Add an entry. The -r option allows an existing entry to be replaced
or a new entry is added if the specified entry does not exist. The
client identifier, Mac address, IP address, and hostname must be
specified. If a record is being replaced these values must be
specified to be the same as existing values in the database. The
lease time should also be specified.
-d Delete an entry. A single key in the form of client identifier, Mac
address, IP address, or hostname should be specified.
-u Update lease time. Specify a key and the lease time using the -T
-p Print an entry for the given key. This can also be used to print
leases expiring in more or less than a specified number of seconds.
-X Specifies that the client identifier is a colon separated string of
bytes in hexadecimal in the specified input or in the output. If
this option is not specified the client identifier is assumed to be
Specifies the client identifier key.
Specifies the Mac (physical interface) address as a string of bytes
in hexadecimal, separated by colons.
This is the hostname (usually fully qualified) as it appears in the
-I IP address
Specifies the IP address as a dotted decimal address string.
-T lease_seconds|absolute time
Specifies the lease time in seconds. With the -p option the lease
time can be specified to print the leases that expire in less than
or greater than a given number of seconds from the current time. For
example -p -T <100, and -p -T >100 prints leases expiring in less
than 100 seconds and more than or equal to 100 seconds respectively.
The format -T "sec[0-61] min[0-59] hour[0-23] mday[1-31] mon[0-11]
years_since_1900" can also be used to specify the time when adding
or updating an entry. For example -T "10 12 20 18 4 98" means the
lease should expire on May 18 21:12:10 1998. The format is the same
as is used with the mktime(3C) call. Alternately -T seconds can be
used to specify the time in seconds from 00:00:00 UTC, January 1,
1970 (see time(2)). For example in the particular case discussed
above the option would be specified as -T 895551130.
With the -a and -u options the lease can be specified as INF for an
infinite lease or as STATIC for a static (infinite) lease. For
example, to make an existing lease for address 10.0.10.1 static the
command is dhcpdb -I 10.0.10.1 -u -T STATIC.
-f Specifies an alternate database to use. The default is
File mode usage
In the file mode the command can be used to dump the entire database to a
file that can be subsequently loaded into the database.
-D Dumps the database to the standard output. The file consists of
fields separated by tabs and includes the client identifier, Mac
address, IP address, hostname, and the lease time.
-L Loads the database from the standard input.
The /etc/ethers and /etc/hosts are not updated when the DHCP
/var/dhcp/etherToIP database is updated.
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