portmap messages under /var/log/messages

["Mike Starr" <starr homemail com>]

I am running Redhat 6.1 as a firewall between a cable modem and my home
network.

Occasionally, I see messages such as these under /var/log/messages:
Jan 17 13:38:16 saturn5 portmap[3726]: connect from 24.28.77.200 to dump():
request from unauthorized host
Jan 18 14:00:34 saturn5 portmap[1544]: connect from 204.151.148.146 to
dump(): request from unauthorized host

My assumption is that the service is fulfilling its purpose of rejecting
unauthorized traffic.  However, I'm curious.  Search as I will, I have been
unable to find any information about dump() that apparently is being probed
on random IP addresses.

Can anyone clue me into this?