I hesitate to raise this as a new post as I am sure I have seen something on this before (from Alien Bob?) but I could not find it by searching the forums.

Slackware 12.1, kernel 2.6.24.5-smp, KDE 3.5.9 usually running.

When my laptop boots up and I am at home I have both eth0 and wlan0 up and running. My question is : how does the system decide which interface to use for any given access request? I ask because it often (stupidly) seems to use wlan0 which is slower than eth0. I can of course manually stop wlan0 before doing some netowork-intensive task, but is there a way to tell the system that it should use eth0 first and only use wlan0 if eth0 seems busy / unavailable ?

Again apologies if this has been answered before.

Bogus Zaba

This sounds useful under those circumstances:
http://www.slackware.com/~alien/slackbuilds/ifplugd/
I haven't tried it myself, not got round to setting up wireless on my laptop yet.

That appears to be something that decides which IF to bring up. My read of the OP is that he wants to know how traffic is routed when there are two active connections.

I have not researched this, but here is a start:
http://www.google.com/search?hl=en&r...ux&btnG=Search

Routing traffic over two different connections can be a bit complicated, but it is possible.
Normally your routing table (try route -n and see your default gateway) decides which interface is used.
You can select interfaces with ip route & ip rule commands.

On this page I wrote about my experiences.

OK I found what I thought existed - Two of Alien Bob's scripts described here :
http://www.slackware.com/~alien/rc_scripts/ifcfg/
One of these uses ifplugd referred to above by BrianL (thanks). In fact following BrianL's post, I got hold of ifplugd and I find that this alone almost does solve the problem, because ifplugd very quickly detects the plugged interface if it is there allowing me to configure the wireless interface (manually with a rc.inet1 wlan0_start command) only if I feel the need. Otherwise I rely on ifplugd to start and stop eth0 - the fast option.

But Alien Bob's second script - which uses ifmetric provides some additional functionality. He says in the README : . Have not tried this additional sophistication yet but this certainly sounds like what I was looking for (and had found some time ago, but lost due to inefficient bookmarking...)