Slackware Client Setup

Downloading the client daemon (dhcpcd)
Depending on your distribution you might have to download the DHCP client daemon. If you want to compile it from the source you package you need is called dhcpcd.

Then follow the instructions below. They should be the same.
3.2. Slackware
You can download the latest copy of the DHCPcd from any Metalab mirror or following:

ftp://metalab.unc.edu/pub/Linux/system/network/daemons
ftp://ftp.phystech.com/pub/ (Primary site)
Download the latest version of dhcpcd.tar.gz.

Unpack it
tar -zxvf dhcpcd-xxxx.tar.gz
cd into the directory and make dhcpcd
cd dhcpcd-xxxx and type
make
Install it (you have to run the following command as root)
make install
This will create the directory /etc/dhcpc where DHCPcd will store the DHCP information and dhcpcd file will be copied into /usr/sbin.
In order to make the system initialize using DHCP during boot type:
cd /etc/rc.d
mv rc.inet1 rc.inet1.OLD
This will move the old network initialization script into rc.inet1.OLD. You now need to create the new rc.inet1 script. Following code is all you need:

#!/bin/sh
#
# rc.inet1 This shell script boots up the base INET system.

HOSTNAME=`cat /etc/HOSTNAME` #This is probably not necessary but I
#will leave it in anyways

# Attach the loopback device.
/sbin/ifconfig lo 127.0.0.1
/sbin/route add -net 127.0.0.0 netmask 255.0.0.0 lo

# IF YOU HAVE AN ETHERNET CONNECTION, use these lines below to configure the
# eth0 interface. If you're only using loopback or SLIP, don't include the
# rest of the lines in this file.

/usr/sbin/dhcpcd
Save it and reboot your computer.
When you are finished go the last step.
After your machine reboots your network interface should be configured. Type: ifconfig.
You should get something like this:

If you have some normal number under inet address you are set. If you see 0.0.0.0 don't despair, it is a temporary setting before dhcpcd acquires the IP address. DHCPcd is a daemon and will stay running as long as you have your machine on. Every three hours it will contact the DHCP server and try to renew the IP address lease. It will log all the messages in the syslog (on Slackware /var/adm/syslog, RedHat/OpenLinux /var/log/syslog).

One final thing. You need to specify your nameservers. There are two ways to do it, you can either ask your provider to provide you with the addresses of your name server and then put those in the /etc/resolv.conf or DHCPcd will obtain the list from the DHCP server and will build a resolv.conf in /etc/dhcpc.
Back up your old /etc/resolv.conf: mv /etc/resolv.conf /etc/resolv.conf.OLD
If directory /etc/dhcpc doesn't exist create it: mkdir /etc/dhcpc
Make a link from /etc/dhcpc/resolv.conf to /etc/resolv.conf: ln -s /etc/dhcpc/resolv.conf /etc/resolv.conf

In /etc/sysconfig/network-scripts/ifup make the following changes 

elif [ "$BOOTPROTO" = dhcp -a "$ISALIAS" = no ]; then
echo -n "Using DHCP for ${DEVICE}... "
/sbin/dhcpcd -c /etc/sysconfig/network-scripts/ifdhcpc-done ${DEVICE}
echo "echo \$$ > /var/run/dhcp-wait-${DEVICE}.pid; exec sleep 30" | sh

if [ -f /var/run/dhcp-wait-${DEVICE}.pid ]; then
^^^^
echo "failed."
exit 1

change it to:
elif [ "$BOOTPROTO" = dhcp -a "$ISALIAS" = no ]; then
echo -n "Using DHCP for ${DEVICE}... "
/sbin/dhcpcd
echo "echo \$$ > /var/run/dhcp-wait-${DEVICE}.pid; exec sleep 30" | sh

if [ ! -f /var/run/dhcp-wait-${DEVICE}.pid ]; then
^^^^^^
echo "failed."
exit 1