Dapper : no connection to the internet

[sebastien]

Hi all,
Ive just installed Dapper 6.06 LTS alternate CD, conserving breezy in
another partition. Everything works fine and fast, except that no
internet connection can be established. When I switch to Breezy,
internet = ok

if config does not show IP address, I cannot connect to my router.

Any clue ?
seb