I've been working on allowing my developers to send emails (Forgot password) from our DMZ web server - Securely.
I enabled SMTP from the DMZ web server IP to the exchange server IP on our firewall.
Set up a new receive connector using only the DMZ web server's IP address and port 25.
-Tried every combination of check boxes (TLS, Basic, Externally secured, anonymous, ect...)
-The ONLY way the email goes out is if I check off "Externally Secured".
-All other combinations return 571 - Authentication errors.
Here is my question...
With "Externally Secured", am I at risk of having someone outside of the company use my exchange server to send email?
If so, what other options do I have...other than Externally Secured?