Using lulu on osx in home business setup. Any reason for external router base firewall?


I have Lulu setup under osx on my Mac. So say an errant program, curl, if it tries to access outside address is stopped.

Would an external router based firewall bring any extra level of protection? I surmise that it will not be fine-grained enough to stop a particular process.

I believe that outgoing request are more risky than incoming request as I do not have any programming listening for request. e.g. No web server enabled.

What use would external router based firewall bring?