$ host -t NS us-east-1.amazonaws.com
    us-east-1.amazonaws.com name server pdns5.ultradns.info.
    us-east-1.amazonaws.com name server ns3.p31.dynect.net.
    us-east-1.amazonaws.com name server pdns1.ultradns.net.
    us-east-1.amazonaws.com name server pdns3.ultradns.org.
    us-east-1.amazonaws.com name server ns4.p31.dynect.net.
    us-east-1.amazonaws.com name server ns1.p31.dynect.net.
    us-east-1.amazonaws.com name server ns2.p31.dynect.net.
    us-east-1.amazonaws.com name server u1.amazonaws.com.
    us-east-1.amazonaws.com name server u2.amazonaws.com.
    us-east-1.amazonaws.com name server u3.amazonaws.com.
    us-east-1.amazonaws.com name server u4.amazonaws.com.
    us-east-1.amazonaws.com name server u5.amazonaws.com.
    us-east-1.amazonaws.com name server u6.amazonaws.com.