Authentication not supported for AUTH NTLM

[kasunramkr]

I am trying to send an email using smtp.lua for "AUTH NTLM" authentication-based server, but keep getting "authentication not supported".

[alerque]

This sounds like the SMTP server isn't setup for the authentication scheme you are trying to use. Check that you are connecting on the expected port and fulfilled any prerequisites (e.g. POP before auth schemes), and that the auth scheme is enabled on the server. Use telnet / netcat to connect directly to verify you can send messages using the expected dialogue for a scheme.

[kasunramkr]

I also checked the "auth" function in smtp.lua:92 as well, looks like authentication only can be done for "AUTH LOGIN" and "AUTH PLAIN" based. So the solution should be, to make my SMTP server supports one of these authentication schemes?

[alerque]

As it is Microsoft specific and that's not a world I run in I'm not familiar with NTLM. It is quite possible the SMPT library we bundle as a side gig doesn't know about the scheme. The socket library itself should support the connections you need, but you might have to come up with the dialogue to use yourself. Or switch to a more generic scheme on the server side.

A PR that adds NTLM support would be considered if it doesn't add any dependencies or degrade the library in any other way. Parity with LOGIN and PLAIN should be a reasonable feature improvement (just one I'm not going to be writing myself!).