Can't use modem while connected to LAN????

Hi there,
Here's my problem:
I am using a laptop. Sometimes I connect that laptop to my home LAN with an ethernet card. Sometimes I use the modem to connect to earthlink and access the internet. I cannot use both at the same time. If I am connected to the LAN and get an address with pump then the modem will dial and connect to earthlink, get an address, and sit there like it is ready to go. However, nothing gets routed out through the ppp link. If I am not connected to the LAN and put in my ethernet card and get a dhcp address with pump while online, my link to the internet goes dead. What do I have to do to allow me to dial up while connected to the LAN. I have been looking for a solution to this for a long time. How do I keep the ppp link open to routing?

still no help, eh?
I notice by reading through the forums that may people have this problem but everyone describes it differently and many people do not post the problem to the networking forum. C'mon folks. This is a routing issue, no? All traffic goes out over eth0 rather than trying ppp0. What do I have to do to make sure the packets go out over ppp0 if the servers are not found on eth0?
I have searched for an answer to this for months, but have been unable to find the answer. Maybe I'm asking the wrong question. Anyone else having this problem: how do you describe it?

yeah, me too...I'm using a desktop at work, pII, 64M, knx-hdinstalled (3.2)...it has both eth card and internal modem (hard modem)...the three external hard modems I tried yesterday were not being found by kppp _or_ pppconfig, finally got the internal to work.

Then, it would dialup, but no name resolution, so I tried

ifconfig

and eth0 was there, hanging out....

so I killed eth0 with

ifconfig eth0 down

I disconnected from the net, and restarted kppp (which is what I was using in the end), and everything worked fine.

Reboot this am, and eth0 is still there, causing the same probs. This computer needs to go out to a client, who only speaks russian and is a pensioner, and I'm trying to set it up for them so it's all easy (big fat icons on desktop kinda stuff) - any ideas on how to stop eth0 from appearing?

I've read a lot of these forums, and I note that it has also been asked, but not answered, here:
http://www.knoppix.net/forum/viewtopic.php?t=3326
and here:
http://www.knoppix.net/forum/viewtopic.php?t=4094
(this one includes other links)....

===============================
ok, after some brainstorming here's what I got, in reference to my original post above, and in particular to eeee's post from sept 20 found here:
http://www.knoppix.net/forum/viewtopic.php?t=2711

solution follows:

on my hd install, when I looked at /etc/network/interfaces this is what I saw:

==========================
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

# The loopback interface
# automatically added when upgrading
auto lo eth0
iface lo inet loopback

iface eth0 inet static
address 192.168.0.1
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.254

=============================

which was set up automatically for me by the knx-hdinstall.

As root, comment out the last 6 lines, so the file now looks like this:

====================
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)

# The loopback interface
# automatically added when upgrading
auto lo eth0
iface lo inet loopback

#iface eth0 inet static
# address 192.168.0.1
# netmask 255.255.255.0
# network 192.168.0.0
# broadcast 192.168.0.255
# gateway 192.168.0.254

============================

when I restarted, I could pon no hassles, and surf, without the problems that the eth0 auto config had caused (ie, I no longer have to type in "ifconfig eth0 down" to get name resolution)

I'm not hard<ore, but I've got a feeling it has something to do with knoppix setting up a gateway that I dont need, and this was causing problems with the dialup.

note: I personally prefer pppconfig to kppp, because I can then just put a pon and poff icon on the desktop for our recipients, no hassles with more gui than they, or I, need. I haven't tested this solution with kppp, but I think it would work.

also: this has not led me to re-try the three external hardware modems that Icouldn't find using _either_ kppp or pppconfig - this I leave to someone else.

good luck

This is not a fix for my problem. It looks like what you did was remove your static IP setting for your nic, which may let you get dial up to get online, but how do you connect to your network? I need BOTH eth0 and ppp0 up and running at the same time, so I can communicate with machines on my lan and get online simultaneously. Can other people do this? Is anyone connected to a lan and dialed up to an online service at the same time?

Ok, I finally figured it out. This one took a looooong time for such a simple problem. I now use "pump --no-gateway". This seems to work properly on my lan and doesn't disable my dial-up. I have tried it successfully at home many times now and it works every time. I've yet to try it at work but if it DOESN"T work I'll post it here.

Here in the UK a couple of days ago NTLworld broadband had a DNS server problem which too everything out for hours. Normally I would connect using 'eth0' and when I got fed up waiting for the broadband connection to get fixed (you must remember, I wasn't absolutely sure that it was broken) I plugged my old external (serial) modem back in and dialed up on Freeserve.

Although I had a PPP connection on the moden, Kmail and Mozilla still 'looked' at 'eth0' and I could not connect, until I did:-

ifconfig eth0 down

(I think!!!! I cannot do it now, or 'click' - silence....... no post!)

Check man ifconfig or ifconfig --help

Hope this helps, Stoo.....