Outgoing VPN PPTP: How to check if TCP port 1723 and GRE protocol port 47 are blocked or not in Windows 7?

I am trying to connect to a VPN Server (BestUKVPN) but I'm failing each time I try.

I get a "691 error" but the username and password are OK.

I searched and I am told that "port 1723" or 'GRE protocol port 47" being blocked can cause this issue as well.

How can I check them and, in case they are blocked, unblock them?

netstat | find "1723"

Thats all u need.

Oh and to unblock them, this page may help

http://www.manageengine.com/products/desktop-central/help/computer_configuration/configuring_windows_xp_firewall.html

GRE is a protocol, not a port. (A lot of people say "My router isn't blocking any ports" but that's irrelevant.) Your router needs to understand how that protocol works. In particular, assuming that you're using NAT (Network Address Translation), the router will need to replace your private IP address with its public IP address in the outbound packets, then do the reverse on the inbound packets. If your router doesn't understand GRE then you either need to upgrade the firmware or replace the hardware - you'll need to check the manufacturer's documentation.

You could also try a different type of VPN connection. PPTP uses GRE, but L2TP/IPSec and SSTP don't. However, the VPN server will need to support them, and it will need a digital certificate; you will also need a certificate on your computer for L2TP/IPSec. It looks as if "BestUKVPN" only support PPTP, so you'll need to decide whether it's more work to change your router or your server.

From command line, to check Windows Firewall rules for 1723 port:

netsh advfirewall firewall show rule name=all | find "1723"

If you have no results, there are no references to any 1723 port (supposedly not blocking).

If yes, try to search more details about the involved rule. For example:

netsh advfirewall firewall show rule name=all > AllPorts.txt

Then edit AllPorts.txt file and search for 1723 to obtain more info.

To check GRE protocol, try:

netsh advfirewall firewall show rule name=all | find "gre" /i

and repeat the procedure.

Of course, you are always supposed to be able to perform this search at Windows Firewall screen, on Windows Control Panel.

NOTE: I assume you are talking about checking outgoing 1723 TCP port and outgoing GRE protocol. Incoming firewalling rules are only needed if you have some VPN server running inside your computer.