How to disable serial line
 

I just installed Sarge using the new installer.
It was fantastic.
But, it installed kernel 2.6.3 with serial line support, which made me unable to
talk to the network because everytime I sent something to the network, the system always sent it through sl0 interface, which is forbiden by the firewall(shorewall)

How can I get rid of this annoying sl0? I do not know what it does and I do not want to know. Can I disable/remove it without recompiling the whole kernel?

Thanks.

Never played with serial stuff, but what the heck.....

You can see if there is a module loaded with lsmod? Then if there is you can rmmod it and then edit your /etc/modules to get rid of it?

Does the serial or sl0 show up as a net device...if you run ifconfig is it listed?

lsmod shows me slip and slhc.
I tried to rmmod them but it complaint: device busy

It looks like a network device. ifconfig shows it as sl0 and it has ip address and everything.
But in /etc/network/interfaces, there is no sl0
Therefore, system says it is not configured when I ifdown sl0

Can anyone help me out? I do not want to compile kernel for every single sarge+shorewall installation!!
Thanks a lot!

p.s. I do not understand why debian team would install this serial line thing.
It appears in every new debian kernel image. What does it really do??!