NFSv4 : question on the resolution of unknown users and groups

[DENIEL Philippe <philippe.deniel@cea.fr>]

Hi,

I am in the following situation : a file belonging to the user whose 
(uid, gid) is (15678,15678) is to be exported via NFS through a client 
and / or a server than knows nothing about this user (there is no entry 
in /etc/passwd, in the yellow pages or whatever is used to maintain 
users's maps).

When using NFSv3, I see this on the client:

    # ls -ld unknown/
    drwxr-xr-x 2 15678 15678 4096 Mar 28 11:15 unknown/

When using NFSv4 (the rpc.idmapd is running on both client and server 
and is configured homogeneously) I see this:

    # ls -ld unknown/
    drwxr-xr-x 2 nobody nobody 4096 Mar 28 11:15 unknown/

With wireshark I can see that the server itself replies the string 
"nobody" as OWNER and OWNER_GROUP. I guess the libnfslibmap (used inside 
the rpc.idmapd) is not resolving (15678, 15678) and returns an error, 
making the nfsd returning nobody. The nfs-utils-lib that I use is 
1.1.5-1 (it's a F13 machine).
Is what I saw a regular behaviour ? How shoud I configure the client 
and/or the server to have the same display in NFSv4 and NFSv3 when 
querying attributes on objects belonging to an unknown user ?

    Regards

       Philippe