nfs connection: mount hangs

Hi,
I have a problem connecting a linux client to a nfs server. The server
has linux2.6-test4 with nfsd (nfs-utils 1.0.5) runnning (network, the
/etc/exports, etc are OK), the client runs 2.4.22 (nfs-utils 1.0.3) -
when I want to connect to the server I do a:
'mount -t nfs 10.0.0.10:/home /mnt/nfs'
This command never returns and seems to hang, but when I kill it from
another shell, the connection is really established - BUT there is no
connection until I kill the mount command !!
Any hints will be appreciated (since I already had this problem on
other linux, nfs [version] combinations) [I want a diskless
workstation to boot and it gets its kernel from the nfs server (via
nfs!) but times out when it comes to mount '/' ...]
Thanks,
Mario