can not access the internet

[Nina Pham <nina@xxxxxxxxxxx>]

Hi I built a linux dialup server. From my pc, I successfully dial in, I 
can browse the file from my home directory, but I can't ping or access 
internet, even though I can do all that from the linux box. What are the 
possibilities cause of that beside the firewall since I already checks 
the firewall and it ought to work with my current rules. Thanks

Nina