SMTP options

Enable SMTP
Enable/disable SMTP protocol support (AfterLogic XMail Server must be restarted when this flag changed).
SMTP Server Port
SMTP server port (if you change this, you should completely understand what you're doing). By default, it takes the value of Standard SMTP Port = 25
SMTP/SSL/TLS Server Port
SMTP/SSL server port for secure connections
Enable SMTP TLS (STARTTLS)
Enable SMTP TLS (STARTTLS) negotiation (default ''on'').
Enable POP3 Before SMTP Auth
Enable POP3 before SMTP authentication.
Max Message Size
If enabled, limits maximum size of accepted e-mails (in KBytes), messages with greater size are rejected. If disabled. messages of any size are accepted.

Advanced options

SMTP Global Gateway Options
Set global SMTP gateway options. Those can be overridden by specific gateway options.
Default SMTP MX Gateway List
A semicolon-separated list of SMTP servers used by AfterLogic XMail Server to send mails. The definition can also contain additional options in the comma-separated list.
Example:
"192.168.0.1,NeedTLS=2;192.168.0.2"
This has a precedence over MX records.

An SMTP gateway definition inside AfterLogic XMail Server can be followed by a set of configuration options, that are in form of a comma-separated VAR=VAL or FLAG definitions. Currently defined options are:

"NeedTLS" - If set to 1, it instructs AfterLogic XMail Server to try to establish a TLS session with the remote host (via STARTTLS SMTP command). If set to 2, AfterLogic XMail Server will try to establish a TLS session, but it would fail if not able to do so (the remote server does not support STARTTLS, or reject our attempt to negotiate the TLS link).

"OutBind" - Set the IP address of the network interface that should be used when connecting to the remote host. This configuration should be used carefully because AfterLogic XMail Server would fail if the selected IP of the interface does not have a route to the remote host using such IP.
SMTP Auth
If enabled, any SMTP agent (no matter SMTP server or mail client) MUST authenticate to send messages to both local and foreign domains. If disabled, SMTP authentication is required only for sending to foreign domains (relay)
Enable VRFY SMTP Command
Enable VRFY SMTP command usage. This flag may be forced by SMTP authentication.