func validateEmail(address string, resolver core.DNSResolver) (rtt time.Duration, err error) {
_, err = mail.ParseAddress(address)
if err != nil {
return time.Duration(0), errUnparseableEmail
}
splitEmail := strings.SplitN(address, "@", -1)
domain := strings.ToLower(splitEmail[len(splitEmail)-1])
result, rtt, err := resolver.LookupHost(domain)
if err == nil && len(result) == 0 {
err = errEmptyDNSResponse
}
if err != nil {
problem := dns.ProblemDetailsFromDNSError(err)
err = core.MalformedRequestError(problem.Detail)
}
return
}
