a.dns.br has one IP number , which also has a corresponding reverse pointer. fm.br, med.br, eti.br, adv.br, nic.br and at least 100 other hosts use this as a nameserver. a4.a.dns.br, a1.a.dns.br, a2.a.dns.br, a6.a.dns.br, a5.a.dns.br and at least five other hosts are subdomains to this hostname. dns.br is a domain controlled by six nameservers at dns.br themselves. All of them are on different IP networks. Incoming mail for dns.br is handled by two mailservers at registro.br. They are on the same IP network. a.dns.br is hosted on a server in Brazil.