nfs and showmount inconsistency

[cleger at scs.carleton.ca]

Hello list, 

I was wondering if anyone can shed light on the following. 

I have a network server which provides, among other things, an nfs export. 

When I call the 'showmount' command to see who or what is using the export, 
I see IP addresses which are not in my /etc/exports file. The /etc/exports file 
contains no generic addresses, but rather only explicit full IPs of the machines
that I want to allow mounting the share. I am sure that the current /etc/exports
is the one in use, since I have both called /etc/init.d/nfs reload AND rebooted
since last editing /etc/exports. 

Does anyone know what behavior of either nfs or showmount might explain this? 

Thank you for your time, 

Christian