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I have searched the entire Internet and universe for this answer but found nothing.

I have a Zyxel P-660R-D1 provided from my ISP. I know how to open ports and port forward them, but I can not figure out how to block a port/ports.

I have tried to forward some port range to a bogus IP on the private LAN but it did not work.

Is it possible at all with this router?

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It sounds like it is in routed mode, which means anything that is not forwarded is blocked by default as those NAT when they are in routed mode. What does the rest of your network look like and what exactly are you trying to do? – MaQleod May 21 '11 at 21:54

Firewalls block incoming ports by default.

There isn't anything you should do more than that, perhaps you could check if it is open.

You should refer to the manuals in the quick links for more information...

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No they are not. Some common game ports are open by default and that is what I need to block. I have looked in the manual. There is no mention of how to block ports. That is why I came to this forum. – Irina May 21 '11 at 22:42
means more specifically that NAT blocks incoming ports implicitly - there must be an explicit forward for the router to know what to do with the port, otherwise it just drops the connection. I'm not aware of any NAT software that has some ports open by default. I think it's more likely what you're seeing is the result of UPnP, software on computers inside your network is requesting that ports be opened. You might try disabling UPnP on the router. If the router really does have some ports forwarded automatically that you can't just remove from the table, you need to complain to Zyxel. – jcrawfordor May 22 '11 at 0:46
@Irina: INCOMING ports, your game ports are most likely outgoing which are open by default. As your ZyXEL is designed to act as a basic modem/router there is no functionality to blocking outgoing ports, you can only open incoming ports. It is meant to provide you with safe internet, if you want to block internet games for your children then you should be looking into a better firewall or parental controls on the computer... – Tom Wijsman May 22 '11 at 11:33
Thx Tom. Now I understand why they are open. It just sucks that I cannot do anything in the router. I am forced to use this one. But I also have a Linksys WRT54G, which is currently configured as an access point. I am not sure if I can use this as the "main" router and block outgoing ports on it, an have Zyxel (ISP) router forward all traffic to the Linksys. – Irina May 23 '11 at 11:31

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