dhcp

Good day all. I am having trouble setting up dhcp for my linux computer to connect with my cable internet service provider. I have already changed my settings in linuxconf to say dhcp. I have tried all four of the different linux dhcp clients that my distro came with. I have a router, but am not yet using it because I want to be sure that everything else works first. The distribution I am using is Mandrake Linux 8.1. After hours of unsuccessfully trying, I switched out the cable modem for a second one we had, yet the connection still did not work. I also switched the nics and cables, yet the computer was still unable to connect to the internet. I thought for a while that there could be some kind of conflict between the modem and the nic, but even after removing the modem, and double checking my settings, the network would still not work.

I had this problem on my Slackware box...installed dhcpcd -h (I think this is the switch) and the hostname. After countless hours one simple command worked for me. Also if you havent seen this site...try it out:
on DHCPcd
http://www.phystech.com/download/dhcpcd.html
Specific Cable modem provider info
http://www.cablemodeminfo.com/LinuxCableModem.html

That worked for me when I was using AT&T cable, the idea that BogoMips just suggested.

What kinda box are you running a dhcp server from?
Your router should have dhcp in it so when you hook it up set that up and use it as a dhcp server.
Unless your cable modem has a router built into it then you need to set up a computer or use a router to set up dhcp.
Is your cable modem connected to your network thru a switch or a computer?

Preach, does your firewall load before or after your DHCP connects? By default on my RH 7.1 box, my rc.firewall file/iptables configuration stuff loaded *BEFORE* my DHCP, so you need a rule in there that allows the DHCP ports (67 TCP & UDP, if I remember correctly). I had this problem a while back, and figured out what I had done. :)