NFS giving Access via DNS-Exports

Hi,

my Network gots following topology:

Gateway I [10.1.0.1] lab01.labornetz.3315.
|---Row I [10.1.0.255].
\---Gateway II [10.1.0.2] lab11.labornetz.3315.

     |---Row II [10.2.0.255].
     \---Gateway III [10.2.0.1] lab21.labornetz.3315.
          \---Row III [10.3.0.255].

All of that Machines except for lab21 can Access the NFS-Shares with:

/srv/nfs4 *.labornetz.3315(rw,fsid=0,no_subtree_check,nohide,anonuid=99,anongid=100) /srv/nfs4/public *.labornetz.3315(rw,no_subtree_check,nohide)
/srv/nfs4/backups *.labornetz.3315(rw,no_subtree_check,nohide,root_squash,anonuid=99,anongid=100)

The nslookup for lab21 and reverse: http://nopaste.linux-dev.org/?664551
for lab11: http://nopaste.linux-dev.org/?664552

The /etc/exports file: http://nopaste.linux-dev.org/?664553

Output of 'tcpdump -i lan0 host 10.2.0.2 and port 2049 -n': http://nopaste.linux-dev.org/?664558

Uncommenting 17 and 18 will give access to Machine lab21, imho this is more a Workaround than a fix.

Any Suggestion on this?

Regards