Multiple internet providers

[Dima Veselov <kab00m%lich.phys.spbu.ru@localhost>]

Hello,

I have a trivial problem, but found very few information on the internet.

I have multiple internet providers, connected to one NetBSD 5.1 box. What is 
the best practice for serving these? The result I want to have:

Incoming connections are replied by the destination address
Outgoing connection is used depending on source address

As I understand - only Linux have an ability of two default routes. 

What is the best practice for that? Is there a need of using some daemon?

Thanks in advance

-- 
Sincerelly yours