nfs exports and netmask option

Setting up nfs on a redhat ES 4 gives me following issue that i
can't explain.

My nfs was working perfect whith following /etc/exports on the server

/home/test/nfstest    198.9.200.227(rw,sync,no_root_squash)

But after a powerloss and restart of the server it only works with the following.

/home/test/nfstest	    198.9.200.227/24(rw,sync,no_root_squash)

I also had to remove the mount on the client it was giving rubbish.
The client was not down.

if i don't add the /24 netmask option i get following error

exportfs: No host name given with
/home/test/nfstest(rw,no_root_squash)
(ro,async,wdelay,hide,secure,root_squash,no_all_squash,subtree_check,secure_locks,mapping=identity,anonuid=-2,anongid=-2),
suggest
*(ro,async,wdelay,hide,secure,root_squash,no_all_squash,subtree_check,secure_locks,mapping=identity,anonuid=-2,anongid=-2)
to avoid warning

So my question is. Why do i suddenly need to add the netmask option. I am sure it was not there before before the powerloss