Take the 2-minute tour ×

I have a web server, which was working fine. It also was an FTP server and a Windows Remote Desktop server, all working fine. Someone called our ISP to increase the internet speed, and suddenly nothing works - I can connect with Teamviewer, but HTTP, FTP & RD doesn't work.

  • Disabled firewall.
  • Ran Wireshark - the packets don't come through at all.
  • Set the webserver to port 20111, in case the ISP is blocking port 80, and again, the packets didn't come through at all. (localhost:20111 works fine)
  • Port forwarding is set up for ports 80, 21, 3389 & 20111 to (which is the correct address - checked with ipconfig).
  • Restarted router and computer.

I would be very grateful for any help.

share|improve this question

2 Answers 2

If Teamviewer works then the problem is ISP, i suspect. If you could try connecing any computer to the WEB end of the router, and your web server would work, you could confirm it is the case.
TeamViewer works by UDP hole punching, like Hamachi and the likes, i believe, that's why you're able to connect.
I saw an ISP (one that offers GPRS and LTE links) who does not allow for ANY incoming traffic. Looks like one big firewall for all users. I actually called their tech support and they confirmed what i was suspecting. We finally renounced their service, because marketing did not talk about this.

share|improve this answer
I thought that too, but they completely deny it –  wezten Dec 3 '12 at 18:55

Is the machine on the same IP address as before? A typical problem on a lower-class service is that when the ISP makes a change, they end up blowing out your static address.

share|improve this answer
Yes, same IP address –  wezten Dec 3 '12 at 19:00

Your Answer


