Opening Ports on a LinkSys Router - KB Article #1289Related Articles --
When setting up a server behind a router, it is necessary to open communication channels known as "ports" to allow people outside of your network to be able to reach the server inside your network. To enable this, routers allow for a function called "port forwarding", where an administrator indicates which ports should be opened and where those communications should be sent on the network. Also known as "creating a pinhole", this allows for individual services to be available without exposing an entire network to the internet.
This example shows how to add port forwards on a LinkSys router. The router used in the example is a LinkSys BEFSR41 with firmware version 1.45.7. Most LinkSys routers are configured in the same way.
- LinkSys routers are configured via a web browser and listen on port 80 by default. Configuring it is as easy as browsing a web site. Open a web browser from a computer on your network. In the URL bar, type in the IP address of your router. The default is 192.168.1.1 so try using http://192.168.1.1.
- A password box will appear asking you to login to your router. If you've changed this password already, then enter it now. Otherwise, please refer to your router's manual for the default password.
- From the router's main configuration screen, click on the "Advanced" button as shown below:
- On the Advanced page, click the "Forwarding" button to open the port forwarding page as shown below:
- On this screen, you can define what port ranges to open and where they should be forwarded on your network. The meaning of each field is listed below:
- Customized Applications - A name for the port forward.
- Ext. Port - These two boxes are the lower and upper range of ports to forward. As shown by the HTTP port forward, enter the same number in both boxes if you're only forwarding a single port.
- Protocol TCP | UDP - These two checkboxes are for the protocol the router is forwarding for. One or both of these checkboxes must be checked. TCP is the most common.
- IP Address - Enter the internal IP address of the machine that will receive the forwarded connections and data. You only need to enter the last segment of the IP address.
- Enable - Check this box to enable the port forward. Unchecking the box will preserve the settings, but the port forward will not work until it's checked again.
- When you're done setting up all the port forwards you need, click the "Apply" button to save the settings to the router. You can now safely close your browser.
You now have setup port forwards on your LinkSys router that enables other computers to connect to a computer on your network!
In the case that configuring individual port forwarding rules is not an option, most SOHO routers also include the option to place a single computer in a "DMZ", or Demilitarized Zone, for the internal network. This causes all incoming requests to be routed to the computer in the DMZ. These include FTP/FTPS/SFTP/HTTP/HTTPS requests, but can potentially include harmful traffic from the internet as well. If the computer hosting Serv-U has known to be secure and is kept well-patched, navigating to the Advanced menu then the "DMZ Host" menu allows you to list a specific IP address on your network that will be the DMZ host and receive all unspecified incoming network traffic.