stopping a process during boot

rmckibben · 07-09-2007, 07:09 PM

Debian Etch (2.6.1) on compaq laptop with both landline (eth1) and wireless (eth0) capability.

Long story short - dead battery + weak fan = power-off when not using.

At power-on, when disconnected from the landline, during the bootup, the system starts dhclient to get an ip address from eth1 first. It will pause for a long time before it gives up and decides to move on and try getting an ip from eth0. Dhclient gets the address from eth0 quickly, and the bootup proceeds apace.

How do I tell the system not to try dhclient from eth1 during bootup when its not plugged into a landline?

Thanks

Dutch Master · 07-09-2007, 08:02 PM

Time to go to bed, but just to give you a hint on where to look next: try a script with an if/then/else structure. Like so:

Code:

if {eth1 down}
then {dhcprequest eth0}
else {dhcprequest eth1}

You'll need to rewrite it in proper bash to get it working.

ZZzzzzzzzzzzz...........

Junior Hacker · 07-09-2007, 08:20 PM

If you have a default Debian installation, you'll have either network-manager or network-manager-gnome installed. NW will try to link to a network automatically upon boot-up, unless you configure the (eth1) interface properly in /etc/network/interfaces to avoid having network-manager manage it, and you link to that interface manually. In /usr/share/doc/network-manager(-gnome or -kde)/README Debian are some examples of which entries in /etc/network/interfaces that are/are not managed by network-manager.

rmckibben · 07-10-2007, 12:01 AM

Quote:

Originally Posted by Dutch Master

Time to go to bed, but just to give you a hint on where to look next: try a script with an if/then/else structure. Like so:

Code:

if {eth1 down}
then {dhcprequest eth0}
else {dhcprequest eth1}

You'll need to rewrite it in proper bash to get it working.

ZZzzzzzzzzzzz...........

This script goes somewhere in boot?

rmckibben · 07-10-2007, 12:14 AM

Quote:

Originally Posted by Junior Hacker

If you have a default Debian installation, you'll have either network-manager or network-manager-gnome installed. NW will try to link to a network automatically upon boot-up, unless you configure the (eth1) interface properly in /etc/network/interfaces to avoid having network-manager manage it, and you link to that interface manually. In /usr/share/doc/network-manager(-gnome or -kde)/README Debian are some examples of which entries in /etc/network/interfaces that are/are not managed by network-manager.

Thanks, I'll go check this out. When the landline is plugged in everything works hunky dory, click click go go. This pause without the landline is happening long before I get to the login prompt. Without the landline, everything works wireless, click click go go, but you have to wait a while. So... everything seems to be configured properly.

So, I take eth1 off the net-mgr list, and it will boot up with only eth0?
And then if I ever want to plug in the landline, say at a my brother's house without a wireless router, I can somehow ifup eth1 after the boot?

Thanks

Junior Hacker · 07-10-2007, 12:22 AM

Actually, I think all you have to do is take out the word "auto" for eth1 in /etc/network/interfaces to avoid network-manager trying to configure it at boot-up. And to bring it up manually, I don't know because network manager does that for me. I also only use the ethernet once in a blue moon at another place, but boot-up does not lag like what you describe without being linked via ethernet. Maybe it's because I have a $3500.00 high end laptop.
EDIT: Actually, the more I think of it, I don't have an entry for the ethernet in /etc/network/interfaces as it gets linked via DHCP, the entries in /etc/network/interfaces are usually for static IP's and wireless with encryption.
SECOND EDIT: Just remembered, I just did a re-installation a couple days ago and have not had it linked to land line yet.

nx5000 · 07-10-2007, 05:36 AM

You can also hit ctrl-c during this wait time.

Also change some timings for the dhcp probe but you have to be sure of what you are doing!

Or use ifplugd , which will detect a disconnected cable.

BillyGalbreath · 07-10-2007, 09:45 AM

[QUOTE=nx5000]You can also hit ctrl-c during this wait time.[QUOTE]
ctrl+c will stop eth1 from loading, but then cause it to skip over eth0 as well. This in return will cause for an even longer wait time for the MTA to load. Really annoying if you ask me.

For my notebook I have eth0 (wired) and wlan0 (wireless). wlan0 is set to "auto" and eth0 is not. This way, wlan0 will load on boot every time. If I dont get a connection with wlan0, it is very easy to load up eth0:

1) open a terminal and su to root (or use sudo for the following).

2) type: ifdown wlan0 (eth1 for you) and wait for the device to shutdown.

3) type: ifup eth0 and wait for the device to load up. If you have 'dhcp' set in the configs (i dont - i use static) then it will request an ip from the dhcp server at this time. However, if you're like me and use a static ip in your configs and this ip does not work on the current connection just type dhclient eth0 to force eth0 to request a new ip from dhcp server.

Now eth0 is up and wlan0 (eth1 for you) is down. You have to make sure your wireless is down before bringing eth0 up because this has the potential to cause problems (unless you know what you are doing).

nx5000 · 07-10-2007, 09:52 AM

[QUOTE=BillyGalbreath][QUOTE=nx5000]You can also hit ctrl-c during this wait time.

Quote:

This in return will cause for an even longer wait time for the MTA to load. Really annoying if you ask me.

Yes that's annoying but AFAIK that's because your system is not completly configured. exim can be reconfigured for "temporary internet connections".
There is a big difference between "a machine not responding" and "a machine name being not resolved". In case the connection is down and your dns server is not available then a lot of things will hang. This also need special configuration maybe with resolvconf package.