Interfaces configuration and tap0

[Philippe Raxhon <raxhonp@easynet.be>]

 Hi,

I'm running a Debian 2.2 with testing packages. I have 2 network cards:
- eth0: not configured, it's used by pppd (ADSL line) when started.
- eth1: configured as 192.168.1.254, for my local network (configured 
using linuxconf, present in /etc/network/interfaces)

But when I boot, ifconfig showns only lo and tap0 (being the default 
gateway). That means I have to do:
- ifconfig tap0 down
- ifconfig eth1 192.168.1.254
before starting the ADSL connection (that is then the default gateway).

What is tap0?
Why doesn't it "load" eth1? When I start linux in single mode it 
doesnt't load nor tap0 nor eth1.

BTW, I have another problem. I have added some environment variables to 
/etc/profile, but they are not taken into account when I run a xterm 
while they are set in a tty.

Thanks a lot. I hope these questions have not been asked 1000 times.

Greetings

Philippe Raxhon