Allow/Deny in Pool Declaration - Implicit Deny?

[Kelvin Williams]

If I were to allow members of a particular class within a pool.  Do I
implicitly deny all others?  If not, how do I deny all others except for
those I have allowed.  Would a:
 

allow members of "myclass"; 

deny all clients; 

 

service all of the members of "myclass" and no other?

 

Many thanks.

 

kw