DHCPINFO(1)DHCPINFO(1)NAMEdhcpinfo - display values of parameters received through DHCP
SYNOPSISdhcpinfo [-c] [-i interface] [-n limit] [-v 4|6] code
dhcpinfo [-c] [-i interface] [-n limit] [-v 4|6] identifier
The dhcpinfo utility prints the DHCP-supplied value(s) of the parameter
requested on the command line. The parameter can be identified either
by its numeric code in the DHCP specification, or by its mnemonic iden‐
tifier, as listed in dhcp_inittab(4). This command is intended to be
used in command substitutions in the shell scripts invoked by init(1M)
at system boot. It first contacts the DHCP client daemon at system boot
or in event scripts as described in dhcpagent(1M). It first contacts
the DHCP client daemon dhcpagent(1M) to verify that DHCP has success‐
fully completed on the requested interface. If DHCP has successfully
completed on the requested interface, dhcpinfo retrieves the values for
the requested parameter. Parameter values echoed by dhcpinfo should not
be used without checking its exit status. See exit(1).
See dhcp_inittab(4) for the list of mnemonic identifier codes for all
DHCP parameters. See RFC 2132, DHCP Options and BOOTP Vendor Extensions
for more details on DHCPv4 parameters, and RFC 3315, Dynamic Host Con‐
figuration Protocol for IPv6 (DHCPv6), for more details on DHCPv6
The output from dhcpinfo consists of one or more lines of ASCII text;
the format of the output depends upon the requested parameter. The num‐
ber of values returned per line and the total number of lines output
for a given parameter are determined by the parameter's granularity and
maximum values, respectively, as defined by dhcp_inittab(4).
The format of each individual value is determined by the data type of
the option, as determined by dhcp_inittab(4). The possible data types
and their formats are listed below:
Data Type Format dhcp_inittab(4) type
Unsigned Number One or more decimal digits UNUMBER8, UNUMBER16,
Signed Number One or more decimal digits, SNUMBER8, SNUMBER16,
optionally preceded by a SNUMBER32, SNUMBER64
IP Address Dotted-decimal notation IP
IPv6 Address Colon-separated notation IPv6
Octet The string 0x followed by a OCTET
two-digit hexadecimal value
String Zero or more ASCII characters ASCII
DUID DHCP Unique Identifier text DUID
Domain Name Standard dot-separated domain DOMAIN
name, RFC 1035 format
The following options are supported:
Displays the output in a canonical format. This format
is identical to the OCTET format with a granularity of
Specifies the interface to retrieve values for DHCP
parameters from. If this option is not specified, the
primary interface is used.
If a primary interface has not been selected for the
system by ifconfig(1M) or for this command by -i, the
system automatically selects an interface to consider
as primary for the current command invocation. The
selection chooses the interface whose name sorts lexi‐
cally first, and that has DHCP parameters attached.
This selection does not affect system state. Use ifcon‐
fig(1M) to set a primary interface.
The recommended practice in the dhcpagent(1M) eventhook
scripts is to specify the desired interface with -i,
rather than relying on primary selection.
For DHCPv6, the interface name used should be the name
of the physical interface, not one of the logical
interfaces created by dhcpagent.
Limits the list of values displayed to limit lines.
-v4 | 6
Specifies the DHCP version to query. Use -v4for DHCPv4
and -v6 for DHCPv6.
The following operands are supported:
Numeric code for the requested DHCP parameter, as defined
by the DHCP specification. Vendor options are specified
by adding 256 to the actual vendor code for DHCPv4, and
65536 for DHCPv6.
Mnemonic symbol for the requested DHCP parameter, as
listed in dhcp_inittab(4).
The following exit values are returned:
The operation was not successful. The DHCP client daemon might not
be running, the interface might have failed to configure, or no
satisfactory DHCP responses were received.
The operation timed out.
System error (should never occur).
See attributes(5) for descriptions of the following attributes:
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
│Interface Stability │ Committed │
SEE ALSOdhcpagent(1M), ifconfig(1M), init(1M), dhcp_inittab(4), attributes(5)
Alexander, S., and R. Droms, RFC 2132, DHCP Options and BOOTP Vendor
Extensions, Silicon Graphics, Inc., Bucknell University, March 1997.
Droms, R. , RFC 3315, Dynamic Host Configuration Protocol for IPv6
(DHCPv6), Cisco Systems, July 2003.
Mockapetris, P.V. , RFC 1035, Domain names - implementation and speci‐
fication, ISI, November 1987.
May 15, 2009 DHCPINFO(1)