| step | query | auth | servers |
| 1 | 72.255.196.121.in-addr.arpa. | . | (h,c,f,b,g,k,m,a,e,d,j,l,i).root-servers.net. |
| 2 | 72.255.196.121.in-addr.arpa. | in-addr.arpa. | (d,a,b,f,e,c).in-addr-servers.arpa. |
| 3 | 72.255.196.121.in-addr.arpa. | 121.in-addr.arpa. | ns4.apnic.net. ns3.apnic.net. ns2.lacnic.net. apnic1.dnsnode.net. ns1.apnic.net. tinnie.arin.net. sec1.authdns.ripe.net. |
| 4 | 72.255.196.121.in-addr.arpa. | 196.121.in-addr.arpa. | (c,a,b).in-addr.cn. |
| 5 | 72.255.196.121.in-addr.arpa. | 255.196.121.in-addr.arpa. | (dns2,dns1).hichina.com. |
We pick