Mike's Tech Blog

Setting up an open Wifi with an IPcop firewall can be a bit tricky. But not too difficult. You need to have a NIC set up for the Blue interface. This way you can have people connect and use your wifi without getting into your regular (Green) network. A typical scenario would be for a coffee shop what wants to provide free wifi to their customers.

This article assumes that you either know how to set up an IPcop firewall, or have already done so with a Blue interface on it. I will also be non-router specific, as the general idea is the same, but it varies slightly from wifi router to wifi router.

The first thing to do is to hook up a Cat5 cable from the WAN port of your wifi / wireless router to the NIC in your IPcop firewall that is assigned as the Blue Interface. Next, connect a temporary computer to one of the LAN ports of your wifi router.

Here is a diagram of a typical IPcop firewall with a Blue interface connected to a wireless router:

Notice that the wireless router's LAN IP address range is different than the WAN IP range. Additionally, both of these IP address ranges are also different than all of the other IP ranges of the other IPcop interfaces, such as the Green interface.

Once you have logged into the router using a wired CAT5 cable and a temporary computer, go to the WAN set up portion. Sometimes (Linksys) its called "Internet Setup". Assign a static IP to the WAN interface - IMPORTANT - This must be in the same address range as the IPcop BLUE interface, yet outside of the range of the wireless router's LAN DHCP scope. In the diagram above, the IP of the WAN Interface for the router is 192.168.3.2.

While you are logged into the wireless router, go ahead and set up the other parts of the wifi router like the SSID and such. When finished, log off the router, and connect to the IPcop firewall through a computer connected to the IPcop's green interface, and login to the firewall.

Click on Firewall then on Blue Access. Add the IP address of the wireless router that is assigned to its WAN port. In the image above, that would be 192.168.3.2.

One issue that I have occasionally run into, is that it can take up to 5 minutes for the link between IPcop's Blue interface and the wireless router's WAN connection to sync up. During this time, there will be no ability to get to the internet through the wireless router. I don't know why this happens, but in time, it will work.

-- Mike

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