ruby on rails - ActionMailer with NTLM auth (Exchange 2010) -

i have rails application using rails 4.2. how can send mail using exchange 2010 server ntlm authentication? according actionmailer docs:

:authentication - if mail server requires authentication, need specify authentication type here. symbol , 1 of :plain (will send password base64 encoded), :login (will send password base64 encoded) or :cram_md5 (combines challenge/response mechanism exchange information , cryptographic message digest 5 algorithm hash important information)

whatever auth method chose, keep getting error:

net::smtpsyntaxerror: 504 5.7.4 unrecognized authentication type 

so found solution myself. kept getting error because exchange server use requires no authentication, should not pass authentication option @ all:

config.action_mailer.smtp_settings = {   address:              'smtp.yourdomain.com',   port:                 587,   domain:               'yourdomain.com' } 

yes thats right: user_name, passwod , authentication left out.