Servidores DNS Principal (mname) y Secundario (rname)
host: drexelmed.net
class: IN
ttl: 3600
type: SOA
mname: adns1.drexel.edu
rname: dunet-admin.drexel.edu
serial: 29
refresh: 3600
retry: 600
expire: 1209600
minimum-ttl: 3600