go into the Router's status page and
see if it has entries ffor the DNS server
and if it does, then open a terminal
and do a 'more /etc/resolv.conf'

You should see some entries in that
file that have the same 'nameserver'
as what you see in the router.

Make sure the router is set to
do both 'dhcp/distribute address'
and NAT.

Try to go to a page numerically
(199.232.41.10) vs. www.gnu.org
and see if you can.