Trying to set up Debian gateway, can't get DHCP offer

[jvedi]

OK, so I'm trying to set up a Debian gateway/router/firewall on an old Dell machine I had lying around so I could replace the crappy 5-year old D-Link I have now.

I cruised around looking for good tutorials on the subject and finally settled upon this one:
How-To: Set up a LAN gateway with DHCP, Dynamic DNS and iptables on Debian Etch | Debian/Ubuntu Tips & Tricks

I went through all the steps, got a little confused about the DNS server setup (I'll get into that later), and got the servers to start without spitting any errors back at me. I have eth0 set up as the WAN port (connected to the cable modem, set up as DHCP), and eth1 set up as the LAN port (static 192.168.1.1).

I took the machine downstairs to hook it into the main switch and the cable modem, powered it on, and went back to my Windows machine to see if I could get an IP. It worked, except that I got an IP from the end of the range instead of the beginning (192.168.1.199 instead of 100). Not a huge problem. I tried to jump on the internet... nothing: here is where the trouble started. I realized that I may have needed to renew the IP configuration on the WAN interface on the Debian machine, so I SSHd into it and did an ifdown eth0, followed by an ifup eth0. It kept sending out DHCP discovers and nothing was coming back. This is where I'm stuck. I was under the impression that the modem would answer the DHCP discover, and eth0 would be configured with the external IP address.

I also would like some clarification on the DNS server setup, if anyone could help me out. On the second page of the tutorial, he uses lan.debuntu.local as his local domain name; what should I be using?. I really have no idea what this step is for exactly, so anyone who can help explain it to me would be awesome.

Thanks in advance, guys.

[Matey]

sorry I am new to this but may be some one else has the answer?
this is what generally happens;
as for the cable modem.. that is great bcs if you had dsl then I'd think the username and passwd was the problem...but I donno if you already check this but the cable modem may be acting as dhcp server and they usually start giving addresses at a higher number like .100 and are set to give only few addresses as well...(You can always http to it and change the configs)..


the domain-name.local is necessary if your machine is not an actual registered domain server on the internet. (so the machine will keep the domain as local and wont try to introduce it to the internet.) while you and your clients still have access to the net.
regards;


.

[jvedi]

The way I understand it is that the cable modem SHOULD be acting as a DHCP server, or at least a gateway to one. The machine I set up acts as the DHCP server to the rest of my LAN, and it gets an external IP address from the DHCP server of the ISP.

I'm not sure if I understand exactly what you mean by having a local DNS, wasn't my network working fine without one before? I don't think that the D-Link router had one? Can someone clarify this for me?

[rcgreen]

The cable modem transparently connects you to the gateway
at the ISP. They should be set up for DHCP, unless they have
told you otherwise, so your WAN interface should be set up
that way. By far the easiest way to do this is to do the installation
of the OS with the ethernet cable plugged in. It will often
configure itself magically. Check the configuration and reboot.
Rebooting is still the cure for all anxiety.

[jvedi]

OK, so a little bit of progress... I power cycled the cable modem, and that seems to do the trick, eth0 is now configured with the external IP address from Time Warner. The problem now, is that the windows machine I have on the network is not getting any internet connection. Is that an issue I am having with the DNS setup I didn't quite understand? Or does it have something to do with the DHCP server, or iptables?

[rcgreen]

The router will have to either run a "caching name server" or give the client machines the address of the ISPs name server. Temporarily,
you could configure clients manually. The DHCP configuration
on the router is in /etc/dhcpd.conf