Static IP addresses

BCarey · 05-05-2006, 04:29 PM

Hi,

I have a question about static ip addresses. I am installing a laptop for someone, and wireless works fine on networks with dhcp. Unfortunately, at this persons place of work they use static ip addresses. I use Slackware 10.2, and so went in to the /etc/rc.d/rc.inet1.conf file and am able to setup a static ip, but I seem to have to reboot for it to take effect(?). The problem is that I want a static ip only when the computer is at work and the rest of the time I want a dynamic ip. I would ideally be able to switch back and forth without a shutdown.

Is this possible?

Thanks in advance,
Brian

ataraxia · 05-05-2006, 04:45 PM

You can do it with "ifconfig" and "route". To bring up a static IP:

Code:

<kill your DHCP client>
ifconfig eth0 down
ifconfig eth0 inet <your_ip> netmask <your_netmask> broadcast <your_bc> up
route add default gw <your_router>
<edit /etc/resolv.conf for DNS servers>

To switch back to DHCP:

Code:

ifconfig eth0 down
<run your DHCP client>

This is possibly more annoying than just rebooting.

Master of Reality · 05-05-2006, 05:28 PM

if you edit the rc.inet1 stuff like you said, you can just run "/etc/rc.d/rc.inet1" (or it may be "/etc/rc.d/rc.inet1 start".

You could copy that script and then modify it to be static, rename the script to something like rc.inet-static and then make it executable so that when the laptop is at work you run that script to start the static IP

BCarey · 05-05-2006, 05:47 PM

Thank you both. I will try atraraxia's suggestion, as this is the "kind" of answer I was looking for. I currently use similar commands/scripts to switch between networks, I just couldn't interpret the man page properly to find the inet thing for a static ip address.

Brian

BCarey · 05-06-2006, 12:05 AM

It worked great. Thanks ataraxia.

Brian

urka58 · 05-06-2006, 04:30 PM

I understand you want to be able choosing dhcp or static IP at boot. If yes, it is a very simple task on Slack.
Just create a second config file, let's say /etc/rc.d/rc.inet2.conf and configure it to work with static IP address.
Then create a second block for your kernel in use on your /etc/lilo.conf like

#fisrt block with dhcp
image = /boot/vmlinuz
root = /dev/hda6
label = Linux-dhcp
read-only
#second block with static IP
image = /boot/vmlinuz
root = /dev/hda6
label = Linux-static
append = "static_IP"
read-only

And last, edit your/etc/rc.d/rc.inet1 this way:
when it says

# Get the configuration information from /etc/rc.d/rc.inet1.conf:
. /etc/rc.d/rc.inet1.conf

edit with

if /bin/cat /proc/cmdline | grep -w static_IP 1> /dev/null 2> /dev/null; then
. /etc/rc.d/rc.inet2.conf
else
. /etc/rc.d/rc.inet1.conf
fi

That's all
Hope this helps
Ciao