Sending mail on localhost smtp does not work - email

Question

I am trying to send an email to the localhost stmp server. I am using fakesmtp program to receive email from localhost.
Look at following code snippet
package mail
import (
"encoding/base64"
"fmt"
"log"
"net/mail"
"net/smtp"
"strings"
)
func encodeRFC2047(String string) string {
// use mail's rfc2047 to encode any string
addr := mail.Address{String, ""}
return strings.Trim(addr.String(), " <>")
}
func Send() {
// Set up authentication information.
smtpServer := "127.0.0.1:2525"
auth := smtp.PlainAuth(
"",
"admin",
"admin",
smtpServer,
)
from := mail.Address{"example", "info#example.com"}
to := mail.Address{"customer", "customer#example.com"}
title := "Mail"
body := "This is an email confirmation."
header := make(map[string]string)
header["From"] = from.String()
header["To"] = to.String()
header["Subject"] = encodeRFC2047(title)
header["MIME-Version"] = "1.0"
header["Content-Type"] = "text/plain; charset=\"utf-8\""
header["Content-Transfer-Encoding"] = "base64"
message := ""
for k, v := range header {
message += fmt.Sprintf("%s: %s\r\n", k, v)
}
message += "\r\n" + base64.StdEncoding.EncodeToString([]byte(body))
// Connect to the server, authenticate, set the sender and recipient,
// and send the email all in one step.
err := smtp.SendMail(
smtpServer,
auth,
from.Address,
[]string{to.Address},
[]byte(message),
//[]byte("This is the email body."),
)
if err != nil {
log.Fatal(err)
}
}
When I executed the send function, I've got the error unencrypted connection. Why?

Answer 1

Most likely the server does not allow you to use plain-text authentication over an unencrypted connection, which is a sensible default for almost any MTA out there. Either change authentication info to e.g. digest, or enable SSL/TLS in you client code.
Remember to use tcpdump or wireshark to check what is actually transmitted.