Please turn on SMTP Authentication in your mail client

[JotaCe14]

Hello I have a problem using the smtp image, because sending mails directly to my SMTP sever works but using the generic relay configuration produces the following error: Please turn on SMTP Authentication in your mail client.

The specifications are:

SMTP relay creation:

docker pull ixdotai/smtp:latest
docker run -p 25:25 -e SMARTHOST_ADDRESS={MY-HOST} -e SMARTHOST_PORT=26 -e SMARTHOST_USER={MY-USER} -e SMARTHOST_PASSWORD={MY-PASSWORD} -e SMARTHOST_ALIASES=*.{MY_HOST} -e MAILNAME={MY_HOST} ixdotai/smtp:latest

SMTP client creation:

docker run -it ubuntu bash
apt-get update
apt install swaks
swaks --to jose.bustamante@dbtarget.pe --server host.docker.internal:25 --from payouts@{MY_HOST}

SMTP relay server result:

289 Connecting to {MY_HOST} [192.185.82.162]:26 ...  TFO mode sendto, no data: EINPROGRESS
289  connected
289   SMTP<< 220-{MY_HOST} ESMTP Exim 4.96.2 #2 Thu, 30 Nov 2023 11:20:58 -0600
289          220-We do not authorize the use of this system to transport unsolicited,
289          220 and/or bulk e-mail.
289   SMTP>> EHLO {MY_HOST}
289   SMTP<< 250-{MY_HOST} Hello {MY_HOST} [{MY_IP}]
289          250-SIZE 52428800
289          250-8BITMIME
289          250-PIPELINING
289          250-PIPECONNECT
289          250-AUTH PLAIN LOGIN
289          250-STARTTLS
289          250 HELP
289   SMTP>> STARTTLS
289   SMTP<< 220 TLS go ahead
289   SMTP>> EHLO {MY_HOST}
289   SMTP<< 250-{MY_HOST} Hello {MY_HOST} [{MY_IP}]
289          250-SIZE 52428800
289          250-8BITMIME
289          250-PIPELINING
289          250-PIPECONNECT
289          250-AUTH PLAIN LOGIN
289          250 HELP
289   SMTP|> MAIL FROM:<payouts@{MY_HOST}> SIZE=1519
289   SMTP|> RCPT TO:<jose.bustamante@dbtarget.pe>
289   SMTP>> DATA
289   SMTP<< 250 OK
289   SMTP<< 550-Please turn on SMTP Authentication in your mail client, or login to the
289          550-IMAP/POP3 server before sending your message.  ({MY_HOST})
289          550-[{MY_IP}]:7425 is not permitted to relay through this server without
289          550 authentication.
289   SMTP<< 503-All RCPT commands were rejected with this error:
289          503-Please turn on SMTP Authentication in your mail client, or login to the
289          503-IMAP/POP3 server before sending your message.  ({MY_HOST})
289          503-[{MY_IP}]:7425 is not permitted to relay through this server without
289          503-authentication.
289          503 Valid RCPT command must precede DATA
289   SMTP+> QUIT

When using swaks directly to SMTP remote server:

swaks --to jose.bustamante@dbtarget.pe --server {MY_HOST}:26 --from payouts@{MY_HOST} --body 'Hello' --auth LOGIN
Username: {MY_USER}
Password: {MY_PASSWORD}

=== Trying {MY_HOST}:26...
=== Connected to {MY_HOST}.
<-  220-{MY_HOST} ESMTP Exim 4.96.2 #2 Thu, 30 Nov 2023 11:29:16 -0600
<-  220-We do not authorize the use of this system to transport unsolicited,
<-  220 and/or bulk e-mail.
 -> EHLO 2d6418eb7d6c
<-  250-{MY_HOST} Hello 2d6418eb7d6c [{MY_IP}]
<-  250-SIZE 52428800
<-  250-8BITMIME
<-  250-PIPELINING
<-  250-PIPECONNECT
<-  250-AUTH PLAIN LOGIN
<-  250-STARTTLS
<-  250 HELP
 -> AUTH LOGIN
<-  334 VXNlcm5hbWU6
 -> {MY_B64_USER}
<-  334 UGFzc3dvcmQ6
 -> {MY_B64_PASSWORD}
<-  235 Authentication succeeded
 -> MAIL FROM:<payouts@{MY_HOST}>
<-  250 OK
 -> RCPT TO:<jose.bustamante@dbtarget.pe>
<-  250 Accepted
 -> DATA
<-  354 Enter message, ending with "." on a line by itself
 -> Date: Thu, 30 Nov 2023 17:28:59 +0000
 -> To: jose.bustamante@dbtarget.pe
 -> From: payouts@{MY_HOST}
 -> Subject: test Thu, 30 Nov 2023 17:28:59 +0000
 -> Message-Id: <20231130172859.000456@2d6418eb7d6c>
 -> X-Mailer: swaks v20201014.0 jetmore.org/john/code/swaks/
 ->
 -> Hello
 ->
 ->
 -> .
<-  250 OK id=1r8kqj-002bFs-02
 -> QUIT
<-  221 {MY_HOST} closing connection

[tlex]

This error normally happens because you're trying to send an e-mail through a relay (the host.docker.internal), however, the sender is configured on the {MY_HOST} domain.

In the second case, you are acting as an e-mail client. In the first case, as an e-mail relay.

I suggest you reach out to your email hoster for {MY_HOST} and clarify with them, what is needed in order to send emails through a relay.

To give you an example from GMail, they have an entire section dedicated to this: https://support.google.com/a/answer/2956491?hl=en