Internet connection but host not found

[McLeod, Peter (Yuetsu)]

Can anybody help me with this problem?  After having installed yellowdog
linux I was able to connect to the internet using kppp (device ttys0) and
access the outside hosts (urls).  A few days later I found that even though
I was connecting to the internet (it logged on and started ppp, etc) I was
unable to find any hosts (e.g.  www.google.com).  How does such a thing
happen?  After this, I completley re-installed my yellowdog linux but had
the same problem - immediatley this time.  Anybody have any ideas?