func answerMX(q *dns.Question, v *DNSValue) dns.RR {
answer := new(dns.MX)
answer.Header().Name = q.Name
answer.Header().Rrtype = dns.TypeMX
answer.Header().Class = dns.ClassINET
answer.Preference = 50 // default if not defined
priority, err := strconv.Atoi(v.Attr["priority"])
if err == nil {
answer.Preference = uint16(priority)
}
if target, ok := v.Attr["target"]; ok {
answer.Mx = strings.TrimSuffix(target, ".") + "."
} else if v.Value != "" { // allows for simplified setting
answer.Mx = strings.TrimSuffix(v.Value, ".") + "."
}
return answer
}
