eth0 and ppp0 fight

motyl · 05-23-2003, 01:23 PM

Hi gurus.

I know this widely discussed topic but I still didn't answer to my question after a week.

Basically what I have is a laptop with eth0 adapter which has static ip address, subnet and gateway. Works fine when I'm in the office connected to local network.
When I'm at home, I need to connect using pppd. Connection is successful, but pppd gives me this message: "not replacing existing default route to eth0 [192.168.0.253]" even though this is unavailable coz I'm not on the local network. I tried to run "route del default" and "route add default ppp0", which works fine, but when I'm back in the office connected to the local network, then it doesn't work as the default route is deleted. This tells me there must be another way of doing this.

Any ideas?

THANKS VERY MUCH FOR HELP!

manthram · 05-23-2003, 01:30 PM

i think you can do that. but it is a very advanced routing topic.

you might want to take a look at this

Half_Elf · 05-23-2003, 01:35 PM

well... What's about a little bash script?
Make it check for network at boot and then remove the default route if there's not network.
Something like this :
NET=`ping -n 1 192.168.0.1` #Any command that can make you sure you're alone
NET=`grep "timeout" $NET
if [ $NET = "" ]; then
route del default
fi

This is a very bad script, I'm sure you can do better. Just put it in rc.local, so you system will execute it at every boot. Maybe you should add a "else" sentence to add a default route if you're on your network.

motyl · 05-23-2003, 04:16 PM

Thanks for your responses folks, they helped me to solve my problem

I've added a script /etc/deletedefaultroute which contains this:

Code:

#!/bin/sh

NET=`ping -c 1 192.168.0.1 | grep "0 received"`
if [ "$NET" != "" ]; then
	echo $NET
	echo network not found, deleting the original default route to eth0
	route del default
else
	echo network found, keeping the original default route to eth0
fi

Then I added a new line at the end of /etc/rc.d/rc.local so it now contains:

Code:

#!/bin/sh
#
# This script will be executed *after* all the other init scripts.
# You can put your own initialization stuff in here if you don't
# want to do the full Sys V style init stuff.

touch /var/lock/subsys/local

/etc/deletedefaultroute

And that's it

Basically what happens is that when the machine boots up, it'll check if the lan is accessible. If not, it'll delete the default route. This allows pppd to setup the default route when it establishes the internet connection.

GREAT HELP GUYS, THANKS VERY-VERY MUCH!