[newbie] Kppp settings problem?

[Lorin & Jenny Pino]

Kppp will dial in and establish a connection.  However, I can't access any web sites.  If I try ping www.yahoo.com, I get ping: unknown host www.yahoo.com.  If I try ping 216.109.118.66 as seen on an earlier post, I get connect: network is not reachable.  I am running Mandrake 9.1.  What do I need to change? Thanks!