[CentOS] portmap/NIS mystery

Thu May 31 21:05:46 UTC 2012
Boris Epstein <borepstein at gmail.com>

Hello all,

I have a server on my private network that is configured as an NIS server
and mapped to a "public" IP address on a firewall. All other TCP ports
(SSH, iperf, you name it) are visible from the outside - but the
portmapper-managed ports (port 111 itself and the YPSERV/YPXFRD ports,
etc.) are not visible from the outside - even though they are alive and
well on the internal network.

So, here's the question: is there anything special as far as portmapper's
networking/security setup that is at play here?