Firewall and Pac Bell DSL...

Greetings! When I installed LinNeighborhood on my laptop, I was expecting only to see two computers. Instead, I saw the entire neighborhood on the other side of my Pac Bell DSL. This is the first time that I have ever ran into this situation where I could see computers beyond the two that I have. I'm using SuSE firewall 2 and SuSE 7.3 on my server with two NICs. I also have Samba running on this machine as well. I want to make sure that no one can come off the internet to access my shares, and I want to block the other the computers from being visible in Win/LinNeighborhood. Short of moving my Samba server to a different computer, any idea how I can fix this? Thanks! Christopher