GMS can be configured to force the use of GMS Secure Socket Layer ensuring there is secure encryption between your GMS server and the remote server.
Should the remote end not support SSL, GMS can revert to standard, unencrypted SMTP to deliver the message.
Assuming that you have obtained and installed an SSL key and have the appropriate certificates in place, there are several options for setting how the POST service uses SSL for sending mail to remote mail servers.
The options for outgoing SSL are set up under Mail > Outgoing > Rules.
- SSL Mode 0: Disables the use of GMS Secure Socket Layer.
- SSL Mode 1: Use GMS Secure Socket Layer if it is available on the remote machine and fall back to non-SSL if not supported.
- SSL Mode 2: Force the use of GMS Secure Socket Layer, if the remote server does not support GMS Secure Socket Layer the message will not be sent. This option should be used if there is a requirement to send email encrypted from server to server.
- SSL Mode 3: This does not use STARTTLS as it aims to connect directly to the secure SMTP port on the remote server, normally port 465.
- Which Type of SSL Certificate should I choose?
- Does GMS support either SMTPS or SMTP submission?
- What methods can GMS provide for encrypting outbound e-mail?
- Why am I unable to send messages via GMS Secure Socket Layer on Solaris?
Keywords:SSL, POST, Secure, security, smime, S/MIME remote server