Opening Port Problem

logicol · EVDO Newbie Joined: 21 Mar 2006 Posts: 2 Location: Wrexham

Hi,

I have opened up a port on my router/firewall and configured a port forwarding rule to in internal IP address. When I perform a port scan using websites such as www.canyouseeme.org the port I have opened does not respond (as if it were closed). I have attempted to open several ports.

I have taken this router to a different site and configured it in exactly the same way and the port is seen to be open. When another router is put in place of the orginal at the original site, the same problem occurs. The only difference with the set up is that data is routed through a different ISP. The ISP assures me that they do not block any ports.

We have a simple network configuration so data should simply go:

internet --> ISP --> Router. But it seems as though there is somthing stopping data from reaching the router. (Saying that, the internet is working ok).

Any suggestions would be much appreciated, Thanks.

tz1 · Posted: Tue Mar 21, 2006 6:22 am Post subject:

"opening a port" will not create anything on the router itself that will respond to a connection on that port.

The router is working if it works anywhere. Whatever internal computer that is supposed to respond isn't working, or there is a firewall blocking the connection in the first case - it is either upstream or downstream.

The internal computer that does respond has a routing table. If it is going through the corporate network instead of the router, it doesn't matter that the port is allowed to pass through on the router, even if the connection gets there, the return port will be routed to the firewall and dropped.

logicol · EVDO Newbie Joined: 21 Mar 2006 Posts: 2 Location: Wrexham

Thanks for your help. The LAN PC was set to use a proxy server that did not allow the particular protocol that I wanted to use. Should have checked that first really!!