On Mon, Mar 13, 2017 at 04:49:23PM -0300, Jeronimo L. Cabral wrote:
> At the moment, the mail relay is reached just from inside our company and
> several applications use it to send mail through Internet.
If the submission port is only reachable from internal trusted
networks, then authentication is optional. You'll need to make
sure that Postfix will not be listening for port 587 on any public
IP addresses.
> Using mailx is in this manner:
My first encounter with "heirloom-mailx", with SMTP and TLS bolted
in mailx, my is the world getting fancy...
> $ mailx -v -r "f...@mycompany.com" -s "TLS test" -S smtp="10.10.12.5:587" -S
> smtp-use-starttls -S ssl-verify=ignore u...@gmail.com
This is fine, provided that 10.10.12.5 is not reachable from outside via
NAT, and no other IP address reaches the same port 587 service.
--
Viktor.
