I have a mail server setup on Windows Server 2008. All was working fine, until I wanted to map a drive on the server so that I can access files on another machine. Windows prompted me to configure Network Discovery, which I did with the "Home/Office" option rather than "Public". After that, several access points that worked before stopped working, like VNC, SMTP, etc. After reinstalling those packages, things appeared to be working again.

Unfortunately, problems have returned with my SMTP server. I can use an web-based SMTP tester, and it connects in 62msec (as expected). However, if I telnet from my machine on the same LAN, it takes more than 20 seconds to connect! When I try to send messages from Outlook, it times out entirely with the message:

Sending' reported error (0x80042109) : 'Outlook cannot connect to your outgoing (SMTP) e-mail server. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).'

I've checked the firewall settings, I've tried configuring it to use port 587 instead of 25, but nothing gets around this problem. Does any have any useful insights? Thanks in advance!