Puzzling nfs/rpc log message

[Freminlins]

Hello,

I have a number of FreeBSD machines mounting two NetApps via NFS. I
updated one of the machines to 5.4 release. I have no prolems mounting
the filers, but I am getting the following log entry every so often:

  Jul 27 16:36:33 fred rpcbind: connect from 192.168.1.5 to
getport/addr(nlockmgr): request from unauthorized host

I am only getting this for one of the filers. They are both accessed
about the same amount, and are identically configured AFAIK.

Can anyone shed any light on this? I've Googled a bit with no luck.

Thanks,
Frem.