Any one know samsung s5233w wifi setting?

i have TP_Link wireless router Model No.WR841ND.It connect well with s5233w.But When i Start moblile browsing it shows an error "DNS Failed". There is noting wrong with the setting of wireless router.Because i have used it for iphone.I changed setting of s5233w wifi many time.But problem is still there.please help me to solve this problem?

Have you inserted the MAC address of the phone on the router settings??

what is a mac address