Java Mail mystery - SMTP blocked?

Question

I have a Java program which uses javax.mail to send an SMTP message. This program works fine on a Linux box, I want to emphasize that beforehand. When I try this same cod

Answer 1

Although this issue is solved: it might still be useful to point out that some Windows Firewalls block/allow access to ports based on the executable name (rather than purely the port number itself) - so you can end up with one program (say Outlook) being allowed and another (say Java) being blocked.