in.dhcpd(1M) System Administration Commands in.dhcpd(1M)NAMEin.dhcpd - Dynamic Host Configuration Protocol server
SYNOPSIS
/usr/lib/inet/in.dhcpd [-denv] [-h relay_hops] [-i interface, ...] [-l
syslog_local_facility] [-b automatic | manual] [-o DHCP_offer_time] [-t
dhcptab_rescan_interval]
/usr/lib/inet/in.dhcpd [-dv] [-h relay_hops] [-i interface,...] [-l
syslog_local_facility] -r IP_address | hostname, ...
DESCRIPTIONin.dhcpd is a daemon that responds to Dynamic Host Configuration Proto‐
col (DHCP) requests and optionally to BOOTP protocol requests. The dae‐
mon forks a copy of itself that runs as a background process. It must
be run as root. The daemon has two run modes, DHCP server (with
optional BOOTP compatibility mode) and BOOTP relay agent mode.
The first line in the SYNOPSIS section illustrates the options avail‐
able in the DHCP/BOOTP server mode. The second line in the SYNOPSIS
section illustrates the options available when the daemon is run in
BOOTP relay agent mode.
The DHCP and BOOTP protocols are used to provide configuration parame‐
ters to Internet hosts. Client machines are allocated their IP
addresses as well as other host configuration parameters through this
mechanism.
The DHCP/BOOTP daemon manages two types of DHCP data tables: the
dhcptab configuration table and the DHCP network tables.
See dhcptab(4) regarding the dhcptab configuration table and dhcp_net‐
work(4) regarding the DHCP network tables.
The dhcptab contains macro definitions defined using a termcap-like
syntax which permits network administrators to define groups of DHCP
configuration parameters to be returned to clients. However, a
DHCP/BOOTP server always returns hostname, network broadcast address,
network subnet mask, and IP maximum transfer unit (MTU) if requested by
a client attached to the same network as the server machine. If those
options have not been explicitly configured in the dhcptab, in.dhcpd
returns reasonable default values.
The dhcptab is read at startup, upon receipt of a SIGHUP signal, or
periodically as specified by the -t option. A SIGHUP (sent using the
command svcadm refresh network/dhcp-server) causes the DHCP/BOOTP dae‐
mon to reread the dhcptab within an interval from 0-60 seconds (depend‐
ing on where the DHCP daemon is in its polling cycle). For busy
servers, users should run svcadm restart network/dhcp-server to force
the dhcptab to be reread.
The DHCP network tables contain mappings of client identifiers to IP
addresses. These tables are named after the network they support and
the datastore used to maintain them.
The DHCP network tables are consulted during runtime. A client request
received from a network for which no DHCP network table exists is
ignored.
This command may change in future releases of Solaris software.
Scripts, programs, or procedures that use this command might need modi‐
fication when upgrading to future Solaris software releases.The command
line options provided with the in.dhcpd daemon are used only for the
current session, and include only some of the server options you can
set. The dhcpsvc.conf(4) contains all the server default settings, and
can be modified by using the dhcpmgr utility. See dhcpsvc.conf(4) for
more details.
OPTIONS
The following options are supported:
-b automatic | manual
This option enables BOOTP compatibility mode, allowing the DHCP
server to respond to BOOTP clients. The option argument specifies
whether the DHCP server should automatically allocate permanent
lease IP addresses to requesting BOOTP clients if the clients are
not registered in the DHCP network tables (automatic) or respond
only to BOOTP clients who have been manually registered in the DHCP
network tables ( manual). This option only affects DHCP server
mode.
-d
Debugging mode. The daemon remains as a foreground process, and
displays verbose messages as it processes DHCP and/or BOOTP data‐
grams. Messages are displayed on the current TTY. This option can
be used in both DHCP/BOOTP server mode and BOOTP relay agent mode.
-h relay_hops
Specifies the maximum number of relay agent hops that can occur
before the daemon drops the DHCP/BOOTP datagram. The default number
of relay agent hops is 4. This option affects both DHCP/BOOTP
server mode and BOOTP relay agent mode.
-i interface, ...
Selects the network interfaces that the daemon should monitor for
DHCP/BOOTP datagrams. The daemon ignores DHCP/BOOTP datagrams on
network interfaces not specified in this list. This option is only
useful on machines that have multiple network interfaces. If this
option is not specified, then the daemon listens for DHCP/BOOTP
datagrams on all network interfaces. The option argument consists
of a comma-separated list of interface names. It affects both
DHCP/BOOTP server and BOOTP relay agent run modes.
-l syslog_local_facility
The presence of this option turns on transaction logging for the
DHCP server or BOOTP relay agent. The value specifies the syslog
local facility (an integer from 0 to 7 inclusive) the DHCP daemon
should use for tagging the transactions. Using a facility separate
from the LOG_DAEMON facility allows the network administrator to
capture these transactions separately from other DHCP daemon events
for such purposes as generating transaction reports. See sys‐
log(3C), for details about local facilities. Transactions are
logged using a record with 9 space-separated fields as follows:
1.
Protocol:
Relay mode: "BOOTP"
Server mode: "BOOTP" or "DHCP" based upon client
type.
2. Type:
Relay mode: "RELAY-CLNT", "RELAY-SRVR"
Server mode: "ASSIGN", "EXTEND", "RELEASE",
"DECLINE", "INFORM", "NAK" "ICMP-ECHO."
3. Transaction time: absolute time in seconds (unix time)
4. Lease time:
Relay mode: Always 0.
Server mode: 0 for ICMP-ECHO events, absolute time in
seconds (unix time) otherwise
5. Source IP address: Dotted Internet form
Relay mode: Relay interface IP on RELAY-CLNT,
INADDR_ANY on RELAY-SRVR.
Server mode: Client IP.
6. Destination IP address: Dotted Internet form
Relay mode: Client IP on RELAY-CLNT, Server IP on
RELAY-SRVR.
Server mode: Server IP.
7. Client Identifier: Hex representation (0-9, A-F)
Relay mode: MAC address
Server mode: BOOTP - MAC address; DHCP - client id
8. Vendor Class identifier (white space converted to
periods (.)).
Relay mode: Always "N/A"
Server mode: Vendor class ID tokenized by
converting white space characters
to periods (.)
9. MAC address: Hex representation (0-9, A-F)
Relay mode: MAC address
Server mode: MAC address
The format of this record is subject to change between releases.
Transactions are logged to the console if daemon is in debug mode
(-d).
Logging transactions impact daemon performance.
It is suggested that you periodically rotate the DHCP transaction
log file to keep it from growing until it fills the filesystem.
This can be done in a fashion similar to that used for the general
system message log /var/adm/messages and is best accomplished using
the facilities provided by logadm(1M).
-n
Disable automatic duplicate IP address detection. When this option
is specified, the DHCP server does not attempt to verify that an IP
address it is about to offer a client is not in use. By default,
the DHCP server pings an IP address before offering it to a
DHCP/BOOTP client, to verify that the address is not in use by
another machine.
-o DHCP_offer_time
Specifies the number of seconds the DHCP server should cache the
offers it has extended to discovering DHCP clients. The default
setting is 10 seconds. On slow network media, this value can be
increased to compensate for slow network performance. This option
affects only DHCP server mode.
-r IP_address | hostname, ...
This option enables BOOTP relay agent mode. The option argument
specifies a comma-separated list of IP addresses or hostnames of
DHCP or BOOTP servers to which the relay agent is to forward BOOTP
requests. When the daemon is started in this mode, any DHCP tables
are ignored, and the daemon simply acts as a BOOTP relay agent.
A BOOTP relay agent listens to UDP port 68, and forwards BOOTP
request packets received on this port to the destinations specified
on the command line. It supports the BROADCAST flag described in
RFC 1542. A BOOTP relay agent can run on any machine that has
knowledge of local routers, and thus does not have to be an Inter‐
net gateway machine.
Note that the proper entries must be made to the netmasks database
so that the DHCP server being served by the BOOTP relay agents can
identify the subnet mask of the foreign BOOTP/DHCP client's net‐
work. See netmasks(4) for the format and use of this database.
-t dhcptab_rescan_interval
Specifies the interval in minutes that the DHCP server should use
to schedule the automatic rereading of the dhcptab information.
Typically, you would use this option if the changes to the dhcptab
are relatively frequent. Once the contents of the dhcptab have sta‐
bilized, you can turn off this option to avoid needless reinitial‐
ization of the server.
-v
Verbose mode. The daemon displays more messages than in the default
mode. Note that verbose mode can reduce daemon efficiency due to
the time taken to display messages. Messages are displayed to the
current TTY if the debugging option is used; otherwise, messages
are logged to the syslogd facility. This option can be used in both
DHCP/BOOTP server mode and BOOTP relay agent mode.
EXAMPLES
Example 1: Starting a DHCP Server in BOOTP Compatibility Mode
The following command starts a DHCP server in BOOTP compatibility mode,
permitting the server to automatically allocate permanent IP addresses
to BOOTP clients which are not registered in the server's table; limits
the server's attention to incoming datagrams on network devices le2 and
tr0; drops BOOTP packets whose hop count exceeds 2; configures the DHCP
server to cache extended DHCP offers for 15 seconds; and schedules
dhcptab rescans to occur every 10 minutes:
# in.dhcpd-i le2,tr0 -h 2 -o 15 -t 10 -b automatic
Example 2: Starting the Daemon in BOOTP Relay Agent Mode
The following command starts the daemon in BOOTP relay agent mode, reg‐
istering the hosts bladerunner and 10.0.0.5 as relay destinations, with
debugging and verbose modes enabled, and drops BOOTP packets whose hop
count exceeds 5:
# in.dhcpd-d -v -h 5 -r bladerunner,10.0.0.5
FILES
/etc/inet/dhcpsvc.conf
/etc/init/hosts
/usr/lib/inet/dhcp/nsu/rfc2136.so.1
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWdhcsu │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Evolving │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOsvcs(1), cron(1M), dhcpmgr(1M), dhtadm(1M), inetadm(1M), inetd(1M),
logadm(1M), pntadm(1M), svcadm(1M), syslogd(1M), syslog(3C),
dhcpsvc.conf(4), dhcp_network(4), dhcptab(4), ethers(4), hosts(4), net‐
masks(4), nsswitch.conf(4), attributes(5), dhcp(5), smf(5)
System Administration Guide: IP Services
Alexander, S., and R. Droms, DHCP Options and BOOTP Vendor Extensions,
RFC 2132, Silicon Graphics, Inc., Bucknell University, March 1997.
Droms, R., Interoperation Between DHCP and BOOTP, RFC 1534, Bucknell
University, October 1993.
Droms, R., Dynamic Host Configuration Protocol, RFC 2131, Bucknell Uni‐
versity, March 1997.
Wimer, W., Clarifications and Extensions for the Bootstrap Protocol,
RFC 1542, Carnegie Mellon University, October 1993.
NOTES
The in.dhcpd service is managed by the service management facility,
smf(5), under the service identifier:
svc:/network/dhcp-server
Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using svcadm(1M). Responsibility
for initiating and restarting this service is delegated to inetd(1M).
Use inetadm(1M) to make configuration changes and to view configuration
information for this service. The service's status can be queried using
the svcs(1) command.
SunOS 5.10 10 Aug 2004 in.dhcpd(1M)
