forward unknown query

[Junior Arnold]

Hi all,

Sorry if this question has been asked (and answered) before but i've
been googling for sometime with no luck:

Here comes my ques:

I have foobar.com hosted somewhere else with www.foobar.com = 1.2.3.4
and mail.foobar.com = 5.6.7.8.

I have a LAN with 20 PC and i want to do local (internal) DNS where
every PC has a name (pc1.foobar.com = 192.168.0.100, pc2.foobar.com =
192.168.0.101). Hence, I created a master zone called foobar.com.

Now, how do i forward unknown queries such as www.foobar.com or
mail.foobar.com to my hosting service provider's DNS (or perhaps any
internet'able DNS such as my ISP's one)?

Thanks in advance.

Regards,
Jr. Arnold