nlockmgr listen on its own port

[Gabriel Barazer]

Hi,

When starting up the nfsv4 nfsd (with rpc.nfsd -U -N 2 -N 3, and idmapd 
and portmapper already started), rpcinfo -p and netstat -lpn show 
another mapped port than the only one expected to be open : 2049 tcp. 
This port (high port mapped by portmapper) is described in rpcinfo for 
use by "nlockmgr". As I will apply firewall rules and block all port 
except 2049 (nfsv4 is supposed to act only on the tcp port 2049 isn't it 
?), why is this port opened ? the nfsv4 locking manager is supposed to 
communicate through the same port 2049/tcp isn't it ?

rpcinfo -p show the following mapping :
    100000    2   tcp    111  portmapper
    100000    2   udp    111  portmapper
    100003    4   tcp   2049  nfs
    100021    1   tcp  57031  nlockmgr
    100021    3   tcp  57031  nlockmgr
    100021    4   tcp  57031  nlockmgr

any ideas ?

Gabriel