DNS delegation of m.facebook.com updated: May 18, 2013 3:02:38 PM
Delegation
step
query
auth
servers
1
m.facebook.com.
.
(a,l,k,f,j,c,g,b,m,i,e,d,h).root-servers.net.
2
m.facebook.com.
com.
(j,g,h,e,m,i,c,l,d,a,b,k,f).gtld-servers.net.
3
m.facebook.com.
facebook.com.
(a,b).ns.facebook.com.
4
m.c10r.facebook.com.
facebook.com.
(a,b).ns.facebook.com.
5
m.c10r.facebook.com.
c10r.facebook.com.
(a,b).ns.c10r.facebook.com.
We pick a.root-servers.net, one of the 13 root servers (1), and ask it about m.facebook.com and learn that com is delegated to 13 name servers (2), so we ask j.gtld-servers.net where we learn that facebook.com is delegated to two name servers, including a.ns.facebook.com (3), so we ask that one where we see a CNAME from m.facebook.com to m.c10r.facebook.com, so we have to start all over again. We already know that a.ns.facebook.com is authoritative for facebook.com (4) and ask it about m.c10r.facebook.com and learn that c10r.facebook.com is delegated to two name servers (5), so we ask a.ns.c10r.facebook.com and get the following answer:
