Dynamic DHCP or static IP

joeljensen · 03-28-2003, 05:43 PM

Boy does this sound strange.

For my network at work, I have to have a static IP address assigned to my RH8.0 laptop. This is required because of the network arrangement.

I want to have the ability of deciding whether to use the static IP or DHCP on boot. This would allow me to hook up to other DHCP networks.

Could this be done? I was thinking maybe with having a specific run-level that sets up DHCP while the rest use static IP.

Any ideas?

I have no problem having to select the run-level at startup.

Thanks

Texicle · 03-28-2003, 06:52 PM

Your ISP will determine whether you get dynamic or static IP. Most times static IPs are assigned to business accounts while dynamic IPs are usually given to residential (at least with my cable internet company). I don't think you'll be able to control that beyond selecting whether you want a business or residential account. If I'm wrong, someone please correct me. Hope this helps.

joeljensen · 03-28-2003, 08:12 PM

At work, the IP is assigned. Elsewhere, it will be DHCP.

twolf · 03-28-2003, 09:26 PM

I believe that it would be possible to make it work through a shell script that would give you an option to run one of two (or more) options.
ie.: press 1 to DHCP
press 2 to staticIP

Would that be a sollution? I don't know if there is a way of setting up profiles... But if the script would help -- let me know and I'll produce it and send it... (hoping that your shell is BASH and the 'ifconfig' runs smoothly + your network interface is Eth0).

Let me know -- Tomas

david_ross · 03-29-2003, 05:18 AM

I think twolf is right - get a script that copies either "eth0.static" or "eth0.dhcp" to "ifcfg-eth0" then restarts networking.

joeljensen · 03-31-2003, 11:35 AM

Twolf. I think you have a successfull idea. I have already setup run-level 5 as the network at work, run-level 4 as no network, and I could use run-level 2 for other networks.

If you already have a script to do this, maybe other would benifit from seeing it also.

Thank you very much.

david_ross · 03-31-2003, 12:02 PM

This isn't very advanced but it should work OK. Just create 2 files "eth0.dhcp" "eth0.static" and put the relevant details in each. Put this script a startup folder or run it manually. (you will need to create a seperate one for static ip's - just change "eth0.dhcp" to "eth0.static")

Code:

#!/bin/bash

echo Changing to DHCP config.
rm -f /etc/sysconfig/network-scripts/ifcfg-eth0
cp /etc/sysconfig/network-scripts/eth0.dhcp /etc/sysconfig/network-scripts/ifcfg-eth0

echo Stopping eth0.
ifdown eth0

echo Starting eth0.
ifup eth0

joeljensen · 04-01-2003, 01:50 PM

Works like a charm. Thank you.