func answerPTR(q *dns.Question, v *DNSValue) dns.RR {
answer := new(dns.PTR)
answer.Header().Name = q.Name
answer.Header().Rrtype = dns.TypePTR
answer.Header().Class = dns.ClassINET
answer.Ptr = strings.TrimSuffix(v.Value, ".") + "."
return answer
}
