DHCP - automatic network configuration

Almost all networks use DHCP to share network configuration (such as ip-addresses) automatically. This document explains how to setup your own DHCP server using Fedora Core.

Server has static ip-configuration, it shares network configuration to workstations. Required network information consists of

IP-address, identifies the computer on the Internet
Network mask, toghether with IP-address defines which address belong to local network (LAN). Packages to LAN are sent directly.
Gateway, the default router. Connects LAN to Internet.
Nameservers (DNS), returns addresses for server names such as www.iki.fi

All network information must be available and working before it is distributed with a DHCP server. DHCP server simply distributes settings that allready work.

DHCP Server Setup

Install dhcp server.

# yum install dhcp

Create the settings file. The “subnet .. netmask” row defines which network interface (network card) is used, so server’s own static IP-address must be within the block defined.

# /etc/dhcpd.conf # www.iki.fi/karvinen/dhcp.html
subnet 10.0.0.0 netmask 255.255.255.0 {
   range 			10.0.0.10 10.0.0.253;
   option routers		10.0.0.254;
   option domain-name-servers	10.0.0.8;
   option subnet-mask		255.255.255.0;
}

Make the log print on your screen continously so you can fix possible errors.

# tail -f /var/log/messages &

You can end the tail program with ‘fg’, ctrl-C.

Start the server

# /etc/init.d/dhcpd start

Test with a Client

Request network configuration using another computer as a client. Check if you got correct network configuration from server.

client# /etc/init.d/network restart
client# /sbin/ifconfig

If you client got network configuration from your DHCP-server, well done, you have a DHCP server.

If necessary, make it start automatically with chkconfig (don’t do this in Helia labs).

DHCP - automatic network configuration

DHCP Server Setup

Test with a Client

See also