talking to smtp.office365.com

[Thomas Bock]

We use an own implementation of SMTP if the user runs a mail server on his own.
This doesn't work with the MS server, as it requires TLS.
What is best practice for using that server from a Linux host?

[Allen Miglore]

By 'own implementation of SMTP', I'm thinking you've written an SMTP client and now need to work with a STARTTLS type connection with the server.  I had to figure that out a while back.  The trick is to get pxplus to switch the socket to a secure one after it's already open.  STARTTLS isn't like SMTPS or HTTPS where you open a secure connection initially.  Instead, you open a regular [tcp] connection, start the SMTP communication with EHLO, and as soon as you see the server responses indicating STARTTLS is needed, you send it a STARTTLS command, to which it responds with a 220 message indicating it is waiting on you to upgrade the connection.  At that point, print(socket,err=*next)'option'("Secure","") and pxplus will try to upgrade to a secure connection.  If that is successful, you then re-start with the ELHO command and you'll be able to proceed through all the normal sending steps.

[Thomas Bock]

That sounds so easy, but I can't get it working 
I post my sample program below. After 'option'("Secure","") nothing useful is happening any more. I tried many different things and combinations but the program can never send the second EHLO. All I received where many errors 2 or 3 or 11.

Code Select Expand

begin
delay = 3
eol$ = $0D0A$
channel = hfn
open (channel, err = FINISH) "[tcp]smtp.office365.com;587;TLS1.3;CERTIFICATES=IGNORE"
gosub GET_RESPONSE
write record (channel) "EHLO " + nid + eol$
gosub GET_RESPONSE
write record (channel) "STARTTLS" + eol$
gosub GET_RESPONSE
write record (channel) 'option'("Secure", $$) + eol$
gosub GET_RESPONSE
!write record (channel) 'option'("TLS", $$) + eol$
!gosub GET_RESPONSE
write record (channel) "EHLO " + nid + eol$
gosub GET_RESPONSE
FINISH:
write record  (channel,err=*next) "quit" + eol$
close (channel)
end
GET_RESPONSE:
read record (channel, tim = delay, err = FINISH) response$
print str(++i:"#0: "),response$
wait 0
return


[Devon Austen]

If you are trying to change a non secure TCP connection to secure you need to use SETDEV SET directive or the PRINT 'OPTION' mnemonic with SSL/TLS specific options. See SETDEV SET directive, 'OPTION' mnemonic and TCP Options. For an example of switching an unsecure TCP connection to a secure one, see Changing from Non-Secure to Secure.

From your example it looks like you want to replace

write record (channel) 'option'("Secure", $$) + eol$

with

print(channel) 'option'("Secure", "")

[Thomas Bock]

That change has no effect. After sending the secure option I cannot read the answers from the server any more. It accepts everything I send, but does nothing.
Is there a sample code showing a successful change to a secure connection and what needs to be send next in case of smtp?

[Mike King]

Why wouldn't you simply use the standard mail interfaces included with PxPlus.  Simply convert your existing home-grown interface to call the standard interface so your application code remains the same for the most part?

[Mike King]

Just checked and it appears smtp.office365.com does claim to support standard SSL connections on port 465. Using this port should allow you to simply use a initial SSL/TLS connection avoiding the need to issue STARTTLS.

[ChrisKCAi]

As an adjunct to this, I'd like to resurrect a previous question - Previously, SMTP was excluded from requiring OAUTH2 for sending emails via Exchange/365 online. It appears that will no longer be the case in the near future (Sep '25) https://techcommunity.microsoft.com/t5/exchange-team-blog/exchange-online-to-retire-basic-auth-for-client-submission-smtp/ba-p/4114750

We use *web/email throughout our system to send emails and many of our installations use Exchange online as their SMTP server (typically port 587/STARTTLS). In a previous thread about this https://forum1.pvxplus.com/index.php?topic=996.msg3417#msg3417 Mike mentions that requiring OAUTH2 for SMTP would be "problematic" but it appears we are going to have that problem. Is anyone else anticipating this and/or have a proposed solution?

[Thomas Bock]

*web/email works for me. Thank you Mike.
But I have an issue with text attachments. I will start a new thread for that.

[martinp]

I currently use office365 for all office machines, but for pvxplus I use the local linux server with relaying to office365, if the internet is down the messages are still queued up.  This doesn't happen often anymore thought.

I was thinking of switching the smtp to office365 I assume *web/email will work and I hope PvxPlus will continue to ensure this is compatible in the future?