Port forwarding problem

Posted on 2005-05-13
Last Modified: 2010-04-17
First, I'm not even sure this is a router problem...but here goes: Bottom line is that I need to know what to look for when we cannot connect to a customer using port forward and pcAnywhere.

For years we have been successfully doing the following setup: The typical user has a DSL modem connected to a router, and the router is connected to their hub/switch, for a small 3-4 user XP workgroup network.  We assign each computer on the network a static IP, such as, and ...1.41, etc.  We load pcAnywhere v11 host on each one, and set the host ports different for each one, such as 5631 and 5632 for the workstation with the ...1.31 address, and 5641 and 5642 for the workstation with the ...1.41 address, etc.

Then, we set up port forwarding in the router, so that ports 5631 and 5632 forward to, etc.  And normally, this all works great, every time.  But today I spent more time trying to get it working for a customer that used to work in the past, but for some unknown reason, no longer does.

While at the customer site, I had my (distant) office try to connect to the IP currently shown on, like we always do, and could not connect.  I also hooked my laptop into the hub, and tried to connect to their whatismyip address, and had no luck, either, although I understand that some routers don't allow that anyway.  Finally, from my laptop I tried to connect to, and that did work..but of course that doesn't do my any good when trying to reach them from a distant site.

I also checked, and they have no firewall software (which is probably not good!), and their XP firewall was turned off.

My question is 'where do I go from here'?  pcAnywhere simply fails to connect, like it does with other setups in cases where I might key in the wrong public IP address, or maybe I specified the wrong port, etc.  I just don't know what to try, and where to look.  Maybe something in pcAnywhere, or some utility in XP, or talking to tech support for their DSL ISP...when it just won't connect, and you know you have it set up right, where do you look next?
Question by:sasllc
    LVL 5

    Accepted Solution

    Whatismyip may be returning the wrong address.  Check your customer's router setup and compare the router's external interface IP with what whatismyip is telling you.   A discrepancy between the two will confirm the problem.

    Use the IP info from the router rather than whatismyip.
    LVL 4

    Assisted Solution

    Also check the router config (and check it's public IP) to ensure the ports are still forwarded to desired stations.
    LVL 1

    Assisted Solution

    Hello,  can you check the correspondance of the entry port you use in order to point the correct local workstation in the local network using pc anywhere ...
    I understood that , on the router, you forwards port and that you don't use 'port triggering' ? it's that correct .
    So if , whith pcanywhere, you want to point the, you have to set in pcanywhere that you use the port 5641 and 5142 in the both program (master and slave ).

    Best regards


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