How to install and configure a DHCP server in Ubuntu 12.04?
I need a step-by-step tutorial if somebody has one.
4
3 Answers
The first thing You need to do is install the packages we need.
Open up a terminal and type:
sudo apt-get install isc-dhcp-server
There are two main files /etc/default/isc-dhcp-server and /etc/dhcp/dhcpd.conf which we will need to configure so lets take the first.
Open up a terminal and using your favorite text editor type:
sudo vim /etc/default/isc-dhcp-server
You should get the following:
#Defaults for dhcp initscript
#sourced by /etc/init.d/dhcp
#installed at /etc/default/isc-dhcp-server by the maintainer scripts
#
#This is a POSIX shell fragment
#
#On what interfaces should the DHCP server (dhcpd) serve DHCP requests"
#Separate multiple interfaces with spaces, e.g. “eth0 eth1".
INTERFACES="eth0"
Replace eth0 above with the name of your network interface that you want the server to lease addresses on. Onto the next file.
Open up a terminal and type:
sudo vim /etc/dhcp/dhcpd.conf
which should give you the output below.
#
#Sample configuration file for ISC dhcpd for Debian
#
#Attention: If /etc/ltsp/dhcpd.conf exists, that will be used as
#configuration file instead of this file.
#
#
....
option domain-name “example.org”;
option domain-name-servers ns1.example.org, ns2.example.org;
option domain-name “comtech.com”;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;
subnet 10.0.0.0 netmask 255.255.255.0 {
range 10.0.0.150 10.0.0.253;
option routers 10.0.0.2;
option subnet-mask 255.255.255.0;
option broadcast-address 10.0.0.254;
option domain-name-servers 10.0.0.1, 10.0.0.2;
option ntp-servers 10.0.0.1;
option netbios-name-servers 10.0.0.1;
option netbios-node-type 8;
......
}
This needs a little bit of explaining.
- Adjust your settings according to your network requirements.
- The option domain name is your dns zone name. For example mine is set to comtech.com.
- Range should be the range of ip addresses that you want the server to give out to clients.
Now restart the dhcp service by typing:
sudo service isc-dhcp-server restart
Thats it!! Your dhcp server should be running, however it is best to check. Open up a terminal and type:
sudo netstat -uap
which will show you something like the following (look for dhcpd, nmbd, and named):
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
udp 0 0 10.0.0.255:netbios-dgm *:* 1016/nmbd
udp 0 0 10.0.0.255:netbios-ns *:* 1016/nmbd
udp 0 0 *:bootps *:* 4525/dhcpd
udp 0 0 *:netbios-dgm *:* 1016/nmbd
udp 0 0 *:netbios-ns *:* 1016/nmbd
udp 0 0 chris-desktop:domain *:* 1273/named
udp 0 0 chris-desktop.lo:domain *:* 1273/named
udp 0 0 chris-deskt:netbios-dgm *:* 1016/nmbd
udp 0 0 chris-deskto:netbios-ns *:* 1016/nmbd
udp6 0 0 [::]:domain [::]:* 1273/named
-
1Just a word of caution, make sure to use
/etc/dhcp/dhcpd.confand not/etc/dhcp3/dhcpd.conf– pukNov 14, 2013 at 23:09 -
1When I restart the service this message is shown:
stop: Unknown instance: isc-dhcp-server start/running, process 3027. I am not able to start the service. I use Ubuntu 13.10.– JJDApr 13, 2014 at 10:53 -
1good . but make sure you've assigned static IP b4 starting DHCP service– kriznaNov 24, 2014 at 10:05
-
Additional things can be included in the accepted answer
Assign static IP before starting isc-dhcp-server service .
You can reserve IP for devices like printers and linux machines by adding MAC id in the below format inside the particular subnet.
------ host bla1 { hardware ethernet DD:GH:DF:E5:F7:D7; fixed-address 10.0.0.10; } ----
From the Ubuntu community page dhcp3-server by Contributors to the Ubuntu documentation wiki:
Dynamic Host Configuration Protocol (DHCP)
The Dynamic Host Configuration Protocol (DHCP) is a network service that enables host computers to be automatically assigned settings from a server as opposed to manually configuring each network host. Computers configured to be DHCP clients have no control over the settings they receive from the DHCP server, and the configuration is transparent to the computer's user.
Installation
At a terminal prompt, enter the following command to install dhcpd:
sudo apt-get install dhcp3-serverYou will probably need to change the default configuration by editing /etc/dhcp3/dhcpd.conf to suit your needs and particular configuration.
You also need to edit
/etc/default/dhcp3-serverto specify the interfaces dhcpd should listen to. By default it listens to eth0.Configuration
The error message the installation ends with might be a little confusing, but the following steps will help you configure the service:
Most commonly, what you want to do is assign an IP address randomly. This can be done with settings as follows:
nano -w /etc/dhcp3/dhcpd.conf# Sample /etc/dhcpd.conf # (add your comments here) default-lease-time 600; max-lease-time 7200; option subnet-mask 255.255.255.0; option broadcast-address 192.168.1.255; option routers 192.168.1.254; option domain-name-servers 192.168.1.1, 192.168.1.2; option domain-name "mydomain.example"; subnet 192.168.1.0 netmask 255.255.255.0 { range 192.168.1.10 192.168.1.100; range 192.168.1.150 192.168.1.200; }This will result in the DHCP server giving a client an IP address from the range 192.168.1.10-192.168.1.100 or 192.168.1.150-192.168.1.200. It will lease an IP address for 600 seconds if the client doesn't ask for a specific time frame. Otherwise the maximum (allowed) lease will be 7200 seconds. The server will also "advise" the client that it should use 255.255.255.0 as its subnet mask, 192.168.1.255 as its broadcast address, 192.168.1.254 as the router/gateway and 192.168.1.1 and 192.168.1.2 as its DNS servers.
If you need to specify a WINS server for your Windows clients, you will need to include the netbios-name-servers option, e.g.
nano -w /etc/default/dhcp3-serveroption netbios-name-servers 192.168.1.1;dhcp3-server and multiple interfaces
multiple interfaces example
Interface
nano -w /etc/network/interfacesauto lo iface lo inet loopback mapping hotplug script grep map eth1 iface eth1 inet dhcp auto eth0 iface eth0 inet static address 10.152.187.1 netmask 255.255.255.0 auto wlan0 iface wlan0 inet static address 192.168.1.1 netmask 255.255.255.0 up /sbin/iwconfig wlan0 mode TTTTTT && /sbin/iwconfig wlan0 enc restricted && /sbin/iwconfig wlan0 key [Y] XXXXXXXX && /sbin/iwconfig wlan0 essid SSSSSSSS auto eth1Select Interface card
nano -w /etc/default/dhcp3-serverINTERFACES="wlan0 eth0"Configure Subnet
nano -w /etc/dhcp3/dhcpd.confddns-update-style none; log-facility local7; subnet 192.168.1.0 netmask 255.255.255.0 { option routers 192.168.1.1; option subnet-mask 255.255.255.0; option broadcast-address 192.168.1.255; option domain-name-servers 194.168.4.100; option ntp-servers 192.168.1.1; option netbios-name-servers 192.168.1.1; option netbios-node-type 2; default-lease-time 86400; max-lease-time 86400; host bla1 { hardware ethernet DD:GH:DF:E5:F7:D7; fixed-address 192.168.1.2; } host bla2 { hardware ethernet 00:JJ:YU:38:AC:45; fixed-address 192.168.1.20; } } subnet 10.152.187.0 netmask 255.255.255.0 { option routers 10.152.187.1; option subnet-mask 255.255.255.0; option broadcast-address 10.152.187.255; option domain-name-servers 194.168.4.100; option ntp-servers 10.152.187.1; option netbios-name-servers 10.152.187.1; option netbios-node-type 2; default-lease-time 86400; max-lease-time 86400; host bla3 { hardware ethernet 00:KK:HD:66:55:9B; fixed-address 10.152.187.2; } }Check Route
ip route192.168.1.0/24 dev wlan0 scope link 82.16.TT.0/24 dev eth1 scope link 10.152.187.0/24 dev eth0 scope link default via 82.16.TT.UU dev eth1
dnsmasq, a DNS and DHCP server with simple configuration file syntax.