At home dhcp worked great, assigned me an IP, and I could access places on the network and the internet. However, on campus DHCP doesn't work at all. I tried running dhcpcd with combinations of -r and -S to no success. What should I do to get dhcp working on my campus network?

Consult the campus network system-administrator.

Campus networks can be annoying that way. On some, you have to register for each MAC (wired and wireless) for each OS.

Sounds like you aren't registered for your campus network. So, yes, talk to the IT department at your school. I'm sure they have a help line.

Are you sure I need to talk to the IT department? DHCP works in Ubuntu (on a different laptop).

on that laptop (on which dhcp works) do ifconfig ethX . Note down the HWaddr part .

Then in your slackware run
dhclient usually works better for me than dhcpcd.

chmod +x /etc/rc.d/rc.inet1
./etc/rc.d/rc.inet1 start
see what's wrong
probably your LAN card not compiled on kernel
For wifi u can open slackware 12 and laptop thread

(my emphasis)
different laptop
different nic
different mac
different OS
etc
(my emphasis)
Any questions?
<ahem>
<produces megaphone>
<tap tap tap> Is this thing ONNNN <feedback>
<takes a deep breath>
<connection times ou

thats why i told him to try out that laptops mac addr. to see if it really is his registering the mac addr that is stopping him.

yes - spoofing the mac may work, and will rule it out. Registering the other mac is better - not good idea going to sysadmin with a tale of all the cracker tricks you've tried. Talking to sysadmin will be definitive... and solve the issue even if it ain't the mac address.

Shot in the dark:
Are you running 2.6.24.x where x < 4 ?
If so, is this a new problem since upgrading to 2.6.24.x?
If so, then upgrade to 2.6.24.4 - there was a fix in there relating to how the kernel sends DHCP DISCOVER, and it caused some dhcp servers to not hand out ip addresses.

Sorry for long reply, been busy. On your advice I had sent an email to my sysadmin explaining the problem. Two weeks passed and no reply. Then today I felt optimistic, ran dhclient and it worked.

Why would spoofing my MAC address be considered cracking? I mean I'm supposed to have access to my campus network and I'm not being malicious.

My kernel is 2.6.21.5.

I din't say that - I said that the sysadmin may frown upon it.

Spoofing a mac address is a cracking technique. It is used to gain you access where you would not otherwise be allowed.

From what was discussed, you are supposed to have access to your campus network from a registered computer. We may disagree with, even despise, that policy, but it is the one in place. At least, that was the speculation in previous posts.

While intent counts for a lot, the sysadmin may feel that you are circumventing campus IT security. You will probably find you have some contractual obligations concerning that and there are usually quite stiff penalties involved with breaking them.

Much better to let the sysadmin know what you want to do - it is certain that the issue has been considered.

Don't e-mail - do you have any idea how many emails these guys get each day? Go to that worthies office and bang on the door.

Perhaps the lease on the old machine's access expired. (Try the old machine.) Perhaps sysadmin got your email and did something after all? May be worth clearing up.

I had emailed him before and had gotten a timely response so I didn't see a reason to see him in person. I know he made at least one change, the instructions to register for linux is now a bash script instead of a .exe... Note that to register you first need to be connected to the LAN i.e. dhcp needs to be working.

So last night cable (tv + broadband) crashed for everyone in the area. Internet is currently up, and it works in my room (tested on friend's computer), but I can't connect on my slackware computer. The only thing I've changed in the interim is I commented out everything in /etc/inetd.conf. dhclient gives an error saying I'm already registered/have an address, so I don't think the problem is with that.

Here is ifconfig:

Grr, I'm really not sure what's wrong with my network connection. It intermittently stops working. When I try to ping I get an unknown hostname. When I run dhclient it tells me can't bind to dhcp address, address already in use. Ideas?

This is your home connection?
Can you still connect to the campus network?

Sounds like a different problem, and needs a new thread.