This post related to my last posting about configuring Open SUSE 10.3 as a DHCP server. For short & dummy explanation, DHCP (dynamic host configuration protocol) is one service that make the server can provide IP address for all the client which connected to the same network. Beside IP address, DHCP server can provide information to the host about netmask address, broadcast address, domain name, DNS server of that network.
For example : if one computer (let say “host”) -configured to used automatic IP configuration – connects to the network, it will search the server that provides IP address. That host will send request to the DHCP server to get IP address. If there is DHCP server laid on that network, the server will receive the request and will answer with give the host IP address (with additional information like netmask, DNS, and so on). If the host cannot find the DHCP server or it couldn’t receive the answer from the DHCP server, the host cannot connected to the network because there is no IP address configured to its network adapter. Remember, to connect to a computer network all the devices must have at least one IP address.
DHCP server on Linux controlled by a file that named /etc/dhcpd.conf. That file looks like this one :
tedy@file-server:~> more /etc/dhcpd.conf
ddns-update-style none;
default-lease-time 14400;
subnet 192.168.0.0 netmask 255.255.255.0
{
range 192.168.0.5 192.168.0.240;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.0.255;
option routers 192.168.0.4;
option domain-name "apt.co.id";
option domain-name-servers 202.134.0.155, 202.134.2.5;
}
That is a basic example of the DHCP configuration file. If you look to the example configuration above, there are several parameter that must be configured related to DHCP configuration :
default-lease-time
using this parameter we can specify how long an IP address will be valid for each user.subnet
we must specify which subnet mask will be used for our network.netmask
the netmask parameter must correctly defined related to subnet mask that already define before.range
we must set a range of IP address that will put in the DHCP pool. User will accepted on of the IP address inside this pool. This part must be specify correctly (consider to the how many user will be connected to the network) to avoid some user cannot get IP address.option routers
if we must specify which IP address will be used as default gateway, we must define in this section.option domain-namethis part will define the domain name of our network. Leave it blank if we don’t use any domain name in the network.
option domain-name-serversusing this parameter we can specify which server will be used as domain name server (DNS). We can list some DNS server’s address here, just separate them using comas.
Every parameter that already defined must be followed by a semicolon mark (as you can see on the example). After make some changes on the /etc/dhcpd.conf file, we must restart DHCP service in order to make the configuration works. In Linux, we can use the following command to restart the DHCP service :
file-server:/apt #/etc/init.d/smb restart
Shutting down Samba SMB daemon done
Starting Samba SMB daemon done
Ok that’s the dummy explanation about configuring DHCP server using Open SUSE 10.3.