AUTH

The AUTH directive is used to specify the type of SMTP authentication. As of edit 142, EMAILX supports the following authentication methods:

• None: typically used with local relay servers; just omit the AUTH directive

• PLAIN: plain text username/password

• LOGIN: encrypted username/password exchange

• AUTO: EMAILX will select LOGIN if available, else fall back to PLAIN

• XOAUTH2: application must specify the access token as the password

Note that SMTP servers will normally list their supported AUTH options in response to the EHLO message, e.g.

> EHLO microsabio.com

< 250-smtp.abc.xyz.com Hello

250-PIPELINING

250-ENHANCEDSTATUSCODES

250-AUTH LOGIN

etc.

You can see this in the Log file for Loglvl 4 or higher.

In the above case, the server is announcing that it supports just the AUTH LOGIN variation. Some servers, however, will not indicate which AUTH methods it supports until after a secure channel is negotiated, followed by a re-sending of the EHLO command. So the first list might omit the AUTH line, or show it with no options. Then, after the second EHLO, it will report another another list of supported options, similar to the above, but perhaps with variations or additions, corresponding to secure mode.