WNDR4500 Ports won't open

[thomas9706]

Hi,

I am trying to host a Minecraft server via portforwarding, but the router won't let me. I can join the server with my internal IP (IPv4) address, but not via the public IP. I've opened the 25565 port on the router, and checked via http://www.yougetsignal.com/tools/open-ports/ whether the port is opened or not, but the site says it is closed.

Also if I host the server at my parents with a D-Link router, it works perfectly.

What can I possibly do wrong?

[StephenB · Accepted solution]

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@thomas9706 wrote:

There is a modem between the ISP and the router, is it possible that the modem is blocking the port?

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If the modem is actually a gateway, then it is blocking the port.  What is the manufacturer and model number?

[StephenB]

What is between the router and the ISP?  Is it possible that there is a gateway in front of the router instead of a modem?

[thomas9706]

There is a modem between the ISP and the router, is it possible that the modem is blocking the port?

[StephenB · Accepted solution]

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@thomas9706 wrote:

There is a modem between the ISP and the router, is it possible that the modem is blocking the port?

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If the modem is actually a gateway, then it is blocking the port.  What is the manufacturer and model number?

[thomas9706]

The modem is a Cisco EPC3928.

[thomas9706]

The modem actually was blocking the port, I've fixed it in the modem menu. Once in there I could open the port again. Thanks for your help.

[StephenB]

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@thomas9706 wrote:

The modem actually was blocking the port, I've fixed it in the modem menu. Once in there I could open the port again. Thanks for your help.

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Your modem is actually a gateway (modem+router).  You can generally put them into a bridging mode, which turns the router function off.  That would keep it from blocking anything.

But it is fine to double-route, although it does complicate port forwarding a bit (as you discovered).