Frequently Asked Question
Does my MIH-120 XRouter have a built-in firewall, and if so, how do I configure it?

Reference ID: MIH00C0003
Modified on: 2000/08/09

Product Area: Internet Sharing Device
Model: MIH-120 XRouter


The MIH-120 XRouterís firewall capability comes from NAT (Network Address Translation).  Besides allowing the router to do its job of splitting a single IP address into a routed subnet of local IPís, NAT has the effect of blocking incoming access into your network unless that access is in response to a request from one of your computers.  For example, if you request a web page, the router will allow the page through to be displayed within your browserís window.  If you request a file from an FTP site, the download is allowed through and you will be able to save the file to your disk.  However, if someone on the outside is trying to access your network, the access attempt will be seen by the XRouter as data thatís not being requested by someone on your network, so the attempt will be automatically denied. This prevents unauthorized access to your system.

You do have the option to open TCP/IP data ports in the MIH-120 XRouterís Virtual Server function. This will allow specific types of incoming data to be forwarded through the XRouter if you plan to run a web, FTP, or other type of server within your network.

Please note that other than the configuration of the Virtual Server (if so desired), there is no configuration necessary regarding NAT on the MIH-120 Xrouter. NAT will be working from the moment you are online with the unit.

Supporting Information

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