Ports for NIS?

I have a centos 4.4 box I would like to use as my NIS server. How to
setup NIS such that ypserv, ypxfrd, and yppasswd will use fixed ports? I
remember that one of the differences between linux and solaris was that
in linux you could specify the ports for those services. Am I correct?

Now, here is an even easier question: how to setup the firewall at the
host to pass those ports?
--
Mauricio raub-kudria-com
(if you need to email me, use this address =)