.Dd July 8, 1999
.Dt DHCP 8
.Os
.Sh NAME
.Nm dhcp
.Nd configuring
.Ox
for DHCP
.Sh DESCRIPTION
The Dynamic Host Configuration Protocol (DHCP) allows hosts on a TCP/IP network
to configure one or more network interfaces based on information collected from
a DHCP server in response to a DHCP request. This mechanism is often used, for
example, by cable modem and DSL network providers to simplify network
configurations for their clients/customers.
.Pp
Information typically contained within a DHCP response includes an IP
address for the interface, subnet mask, broadcast address, router (gateway)
listing, domain name server listing, and the interface's MTU.
.Pp
In
.Ox ,
DHCP is handled mostly by the
.Xr dhcpd 8
daemon, which issues DHCP requests and configures the local network based on
information gleaned from the replies it receives from a DHCP server.
.Pp
To get started, follow these steps:
.Bl -enum -offset indent
.It
Edit
.Pa /etc/rc.conf
and set
.Cm dhcpd_flags="-q" .
This will cause
.Ox
to start the
.Nm dhcpd
daemon at boot-time and configure any interfaces with their address family
set to
.Dq dhcp .
.It
For each interface that is to be configured via DHCP, create a
.Pa /etc/hostname.XXX
file (where XXX is the interface's identifier, i.e., ep1) that contains only
the word
.Dq dhcp .
.It
Ensure a
.Pa /etc/dhcpd.conf
file exists. This file is shipped with the system and should not be removed.
.It
Ensure the kernel has been compiled with BPF (Berkeley Packet Filter) support
and at least one
.Pa /dev/bpf*
file exists per broadcast network interface that is attached to the system.
This is almost always the case and should only be considered if all other
troubleshooting options have failed.
.El
.Pp
See
.Xr dhcpd 8
for information on other available options; for example,
.Fl p ,
which allows specification of a port to listen on other then the default (67).
However, most of the flags are only useful for debugging purposes.
.Sh NOTES
In addition to
.Xr dhcpd 8 ,
the
.Xr dhclient 8
program may be used for one-time manual DHCP configurations. See its man page
for more information.
.Sh FILES
.Bl -tag -width /etc/hostname.XXX -compact
.It Pa /etc/rc.conf
configuration file where
.Cm dhcpd_flags
must be set
.It Pa /etc/hostname.XXX
interface-specific configuration files
.El
.Sh SEE ALSO
.Xr dhclient 8 ,
.Xr dhcpd 8 ,
.Xr dhcpd.conf 8