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@jim3ma
Forked from chrisgillis/ssl_smtp_example.go
Last active July 1, 2024 00:01
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Golang StartTLS SMTP Example
package main
import (
"fmt"
"log"
"net"
"net/mail"
"net/smtp"
"crypto/tls"
)
// StartTLS Email Example
func main() {
from := mail.Address{"", "username@example.tld"}
to := mail.Address{"", "username@anotherexample.tld"}
subj := "This is the email subject"
body := "This is an example body.\n With two lines."
// Setup headers
headers := make(map[string]string)
headers["From"] = from.String()
headers["To"] = to.String()
headers["Subject"] = subj
// Setup message
message := ""
for k,v := range headers {
message += fmt.Sprintf("%s: %s\r\n", k, v)
}
message += "\r\n" + body
// Connect to the SMTP Server
servername := "smtp.example.tld:465"
host, _, _ := net.SplitHostPort(servername)
auth := smtp.PlainAuth("","username@example.tld", "password", host)
// TLS config
tlsconfig := &tls.Config {
InsecureSkipVerify: true,
ServerName: host,
}
c, err := smtp.Dial(servername)
if err != nil {
log.Panic(err)
}
c.StartTLS(tlsconfig)
// Auth
if err = c.Auth(auth); err != nil {
log.Panic(err)
}
// To && From
if err = c.Mail(from.Address); err != nil {
log.Panic(err)
}
if err = c.Rcpt(to.Address); err != nil {
log.Panic(err)
}
// Data
w, err := c.Data()
if err != nil {
log.Panic(err)
}
_, err = w.Write([]byte(message))
if err != nil {
log.Panic(err)
}
err = w.Close()
if err != nil {
log.Panic(err)
}
c.Quit()
}
@poloyacero
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@so0k If I set InsecureSkipVerify to false is there any more verification I need to implement? Could you guide me on this? Thanks

@vincenthsh
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vincenthsh commented Mar 9, 2023

@poloyacero - depends on the certificate chain presented to your code?

if the server you're connecting to uses a trusted root CA (i.e. Let's Encrypt issued certificate) - then you don't have to do anything (as long as the client running the code has the certificate authorities loaded (which is in all linux, macos, windows distros) it should "just work"

if however, you're using this code in test or local dev where you self sign certificates for testing an smtp server, then you need to drop the verification, or you need to run the right command to trust the root CA that signs the certificates of the host you're testing against

@urko-b
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urko-b commented Mar 13, 2023

thanks so much to share I really appreciate. I would like to know how can I send html in body. Kind regards

@y-vas
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y-vas commented May 18, 2023

@urko-b html goes directly into the body
body := "<div>This is an <b>example</b> body.\n With two lines.</div>"

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