isc-dhcp – ISC Dynamic Host Configuration Protocol server

isc-dhcp – ISC Dynamic Host Configuration Protocol server

Last Updated on 2017-07-02 by Sture


ISC’s Dynamic Host Configuration Protocol Distribution provides a freely redistributable reference implementation of all aspects of DHCP, through a suite of DHCP tools

  • A DHCP server (this port)
  • A DHCP client
  • A DHCP relay agent


Preparation for Installation

Start PuTTY on a Windows PC, Terminal on a Mac or similar terminal application on a Linux PC.

In this example Terminal on a Mac is used.

Open a remote SSH session to the server with:

Mac:~ user$ ssh user@ [enter]
N.B.: Replace user@ with User ID and IP Address on Your server!
[user@server ~]$

Enable superuser privileges with:

[user@server ~]$ sudo -s [enter]
Password: <-- passwd [enter]
[root@server /usr/home/user]#

N.B.: Enter user password, not the root password!


Search for isc-dhcp in the remote package repositories with:

[root@server /usr/home/user]# pkg search isc-dhcp [enter]
isc-dhcp43-client-4.3.5        The ISC Dynamic Host Configuration Protocol client
isc-dhcp43-relay-4.3.5         The ISC Dynamic Host Configuration Protocol relay
isc-dhcp43-server-4.3.5        ISC Dynamic Host Configuration Protocol server
[root@server /usr/home/user]#

In this example, sc-dhcp43-server will be installed.

Install isc-dhcp43-server with;

[root@server /usr/home/user]# pkg install isc-dhcp43-server [enter]
Updating FreeBSD repository catalogue...
FreeBSD repository is up-to-date.
All repositories are up-to-date.
The following 1 package(s) will be affected (of 0 checked):

New packages to be INSTALLED:
	isc-dhcp43-server: 4.3.5

Number of packages to be installed: 1

The process will require 4 MiB more space.
989 KiB to be downloaded.

Proceed with this action? [y/N]: y [enter]
Fetching isc-dhcp43-server-4.3.5.txz: 100%  989 KiB   1.0MB/s    00:01    
Checking integrity... done (0 conflicting)
[1/1] Installing isc-dhcp43-server-4.3.5...
===> Creating groups.
Creating group 'dhcpd' with gid '136'.
===> Creating users
Creating user 'dhcpd' with uid '136'.
[1/1] Extracting isc-dhcp43-server-4.3.5: 100%
Message from isc-dhcp43-server-4.3.5:
****  To setup dhcpd, please edit /usr/local/etc/dhcpd.conf.

****  This port installs the dhcp daemon, but doesn't invoke dhcpd by default.
      If you want to invoke dhcpd at startup, add these lines to /etc/rc.conf:

	    dhcpd_enable="YES"				# dhcpd enabled?
	    dhcpd_flags="-q"				# command option(s)
	    dhcpd_conf="/usr/local/etc/dhcpd.conf"	# configuration file
	    dhcpd_ifaces=""				# ethernet interface(s)
	    dhcpd_withumask="022"			# file creation mask

****  If compiled with paranoia support (the default), the following rc.conf
      options are also supported:

	    dhcpd_chuser_enable="YES"		# runs w/o privileges?
	    dhcpd_withuser="dhcpd"		# user name to run as
	    dhcpd_withgroup="dhcpd"		# group name to run as
	    dhcpd_chroot_enable="YES"		# runs chrooted?
	    dhcpd_devfs_enable="YES"		# use devfs if available?
	    dhcpd_rootdir="/var/db/dhcpd"	# directory to run in
	    dhcpd_includedir="<some_dir>"	# directory with config-
						  files to include

****  WARNING: never edit the chrooted or jailed dhcpd.conf file but
      /usr/local/etc/dhcpd.conf instead which is always copied where
      needed upon startup.
[root@server /usr/home/user]#


List installed services dhcp with:

[root@server /usr/home/user]# service -r | grep dhcp [enter]
[root@server /usr/home/user]#

Find the rcvar for /etc/rc.conf:

[root@server /usr/home/user]# /usr/local/etc/rc.d/isc-dhcpd rcvar [enter]
# dhcpd
#   (default: "")

[root@server /usr/home/user]#

To start isc-dhcp43-server on system boot, add information to /etc/rc.conf with this commands:

[root@server /usr/home/user]# echo '' >> /etc/rc.conf; echo '# ISC dhcpd' >> /etc/rc.conf; echo 'dhcpd_enable="YES"' >> /etc/rc.conf; echo 'dhcpd_ifaces="em0"' >> /etc/rc.conf [enter]
[root@server /usr/home/user]#

Replace the ’em0′ interface name with the interface (or interfaces, separated by whitespace) that your DHCP server should listen on for DHCP client requests.

Edit /usr/local/etc/dhcpd.conf with:

[root@server /usr/home/user]# ee /usr/local/etc/dhcpd.conf [enter]

N.B.: This is an example with support for client PXE Boot!

# dhcpd.conf


default-lease-time 3600;
max-lease-time 86400;

ddns-updates on;
ddns-domainname "";
ddns-rev-domainname "";
ddns-update-style interim;

log-facility local7;

server-name "";

allow client-updates;
allow unknown-clients;
do-forward-updates true;

include "/usr/local/etc/namedb/rndc.key";

subnet netmask {
        option domain-name-servers;
        option subnet-mask;
        option routers;
        option broadcast-address;
        option ntp-servers;
        option domain-name "";
        default-lease-time 3600;
        max-lease-time 86400;
        option root-path "";
        filename "/gpxelinux.0";

# Hosts Forward
zone {
        key rndc-key;

# Hosts Reverse
zone {
        key rndc-key;

Make sure that file /usr/local/etc/dhcpd.conf is not world readable with:

[root@server /usr/home/user]# chmod 640 /usr/local/etc/dhcpd.conf [enter]
[root@server /usr/home/user]#



Manually start isc-dhcp43-server with;

[root@server /usr/home/user]# service isc-dhcpd start [enter]
Starting dhcpd.
Internet Systems Consortium DHCP Server 4.3.5
Copyright 2004-2016 Internet Systems Consortium.
All rights reserved.
For info, please visit
Config file: /usr/local/etc/dhcpd.conf
Database file: /var/db/dhcpd/dhcpd.leases
PID file: /var/run/dhcpd/
Wrote 0 leases to leases file.
Listening on BPF/igb0/00:1b:21:a4:4e:cc/
Sending on   BPF/igb0/00:1b:21:a4:4e:cc/
Sending on   Socket/fallback/fallback-net
[root@srv /usr/home/stureah]#
[root@server /usr/home/user]#

Display isc-dhcp43-server status with:

[root@server /usr/home/user]# service isc-dhcpd status [enter]
dhcpd is running as pid 31662.
[root@server /usr/home/user]#

View content of dhcpd-leases

[root@server /usr/home/user]# cat /var/db/dhcpd/dhcpd.leases [enter]
# The format of this file is documented in the dhcpd.leases(5) manual page.
# This lease file was written by isc-dhcp-4.3.5

# authoring-byte-order entry is generated, DO NOT DELETE
authoring-byte-order little-endian;

lease {
  starts 3 2017/03/01 14:32:06;
  ends 3 2017/03/01 15:32:06;
  tstp 3 2017/03/01 15:32:06;
  cltt 3 2017/03/01 14:32:06;
  binding state free;
  hardware ethernet e4:a7:a0:73:c4:ea;
  uid "\001\344\247\240s\304\352";
  set vendor-class-identifier = "MSFT 5.0";
[root@server /usr/home/user]#

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