WIFI Extension Using a Router (WRT54G)

In general, there are at least two reasons why people want to extend WIFI.  The first situation is where your reception is marginal.  All you need in this case is a PCMCIA card and an antenna.

If on the other hand, you want this to be a more permanent situation, you need different equipment.  This is often the case when you want to connect two buildings together.  One has an Internet connection and the other does not.  You may choose to have several computers in the building that is being connected, so you need a wired or a wireless network to connect them all together.

When I started working on this type of a setup, there were no wireless bridges or any other such item that was in my price range.  I decided to use some of the aftermarket software written for the WRT54G, WRT54GS, or WRT54GL.

Typical System

A typical system is made of source access point and a client.  Many of today’s routers do not support the client mode so that is why you need aftermarket software.  My favorite is DD-WRT #23.  It works on version 1-4 of the WRT54G and all of the others listed above.  It does not work on a WRT54G version 5.  If you are using a DD-WRT be sure to check the version number as you will create a brick if you update with the wrong version of software.  The aftermarket software only needs to be run on the client end as the standard software works fine on the access point end.

The WRT54 series, has a software update feature under the administration button.  You need to download the DD-WRT software and expand that into a directory.  You then do a browse in the update screen and point to the new version of software.  Tell it to update and be sure to give it enough time to finish.  Wait for about two minutes after the lights become stable.

Connect the router #1 to the internet in the first building using one of the LAN ports or to a Cable or DSL box using the WAN port.  Use a laptop or other computer to make sure it is working.  The normal IP address will be so if this will conflict with something else in the existing network, it may need to be moved.  For now lets assume that it is okay.  You log into these routers by using a username of root and a password of admin.   The DHCP server should be running on this Router.

Router #2 will be setup by going to the Wireless page. Change the Wireless Network Mode to Client.  You should also set the SSID to the same SSID as on the source router.  Be sure to do a save after each change.

The second change will be made on the Setup/Basic Setup page.  To keep data from getting confused, you need to create a new subnet, which will have different IP address than the access point router.  I change the Local IP Address to so that I am out of the way of the other network.  To create a subnet you set the Subnet Mask to  This makes everything above 193 on a new subnet.  The starting IP address for the DHCP server should be set to something like .195.  You now do a save and the computer that you have connected may get confused.  You need to do a ipconfig /release and then a ipconfig /renew in a dos box.  Once this is complete you should be able to do a ipconfig/all and see that your new IP address will be something like  If the computer will not connect back up try a reboot.  If that does not work then you must have set something wrong.  A 30 second reset on the router will put it back to factory settings so you can start over.   Here are the router screens that need to be changed and what they should look like:Setup Page

Now lets look at the Wireless page changes:

Wireless page

Router #2 should now be connected, so to check this out, go to the Status tab and then click on Wireless.  Do a site survey and make sure that the two routers can see each other.  If not you will need to add an external antenna.  If they can see each other okay, do a Refresh on the Wireless page and check the data to make sure it has connected correctly.  You should see that it found a DHCP server.  You can now move back to the LAN tab and do a refresh.  The new DHCP server should now show up.

Your new network is now up and running.  If you are going to need wireless in the second building, connect up another router to one of the LAN ports.  Standard software should work just fine.  Change the radio channel on the router to be at least two above or below the channel on the other two routers.  You can connect wired computers to the LAN ports also.

You can now setup your security setting if needed.

If things did not work you need to do some trouble shooting.  Here is an outline:

    1.      My normal trouble shooting requires a laptop which I connect to each router and check for the correct setup.

    2.     Connect to one of the LAN ports on router #1.  The router should give you an IP address, the correct gateway, and the appropriate DNS server.  This can be checked using Ipconfig/all.  No special setup should be needed to make this work.

    3.     Connect to one of the LAN ports on router #2.  Go to the status page and choose the Wireless tab.  Check to see that you are connected.  The SSID should show             up and it should show as connected.  If not try a refresh.  If it still does not connect, go to the wireless survey and see if the access point you want to connect to is shown.  If not you need to move the routers closer together or add an antenna.

    4.     Once you get it connected, check the LAN page.  A refresh there often fixes things also.  It should now show the correct IP address, DHCP server and DNS server.  Once this shows up correctly, your system should be running correctly.

    5.     The above steps can be done from the wireless connection also if the the wireless configuration has not been turned off.

    6.     A few other trouble shooting tips are listed below:

        a.      Tracert can often help you understand where data is going wrong.  Use it to list all systems between you and some known good IP address.

        b.     Ping is often used to see which routers can be seen from any point.

        c.     At times a router that has no DHCP server running will not connect to a laptop which has a 169.xxx.xxx.xxx IP address.  You can fix this situation buy setting a fixed IP address on the laptop to be within the same range as the router.  The default for any of these routers is after a reset.  I often us a fixed IP address of for the laptop.