connection timed out; no servers could be reached nslookup

nslookup 192.168.56.81 ;; connection timed out; trying next origin ;; connection timed out; no servers could be reached There is setting in hostfile and resolv.conf . Ip is pinging. /etc/sysctl.conf --> data is present. kernel.domainname=domain name kernel.hostname=hostname /etc/sysconfig/network --> hostname file entry is present.