I've just setup a machine with Windows Server 2008. It hosts various services, like IIS, POP3, SMTP, Music for Squeezeboxes, VNC. All was working well for the first week or so.
One day I needed to create a mapped drive on the server, so it could access files on my workstation. Windows indicated that Network Discovery was needed, so I turned it on with the "Home / Office" option (rather than "Public").
This may be coincidence, but since that time I've been having troubles accessing various services from my main workstation (running Windows 7/64):
- POP3 continued working correctly, but SMTP was delayed or failed entirely. (Telnet took 20 seconds to connect, but Outlook would never send messages.)
- VNC failed entirely. I reinstalled it on the server, and now it works but feels sluggish.
- The music web server was extremely delayed and usually failed. I tried reinstalling, and now it takes about 30 seconds to show the page name on the browser tab, and another 30 seconds to display any page contents.
Other machines on the local network seem fine, as do machines connected via the Internet.
I don't believe I changed anything on my own machine that would cause this. I considered the possibility that my anti-virus was involved, so I uninstalled AVG (commercial version), but that didn't help. I installed Norton 360 after that, and it didn't complain of viruses on my machine, and the delays remained.
Because only my machine is affected, I'm tempted to place blame there, except that I don't recalling changing anything, and reinstalling software on the server improved the situation. Therefore, there is likely something going on with the server too.
The server's firewall has all the necessary ports open, and it works fine for the other workstations (including external machines connected via the Internet), which indicates that it should be fine.