We pick l.root-servers.net, one of the 13 root servers (1), and ask it about ci-servers.org and learn that org is delegated to six name servers (2), so we ask b0.org.afilias-nst.org where we learn that ci-servers.org is delegated to three name servers, including ns.orange-tree.alt.za (3), so we ask that one and get the following answer: