This post is how to add wifi to a wired network if all you have is a modem/wireless/router unit but without a WAN port to plug into, just LAN ports.
I have an actiontec wireless n dsl modem with built in wifi and router capabilities (model GT784WN-01 ), but I dont want to use it as a modem – I want to use it to add a wireless access point for an existing wired network. At first I thought it would be easy to just plug into an existing network cat5 cable into the modem/wifi/router without needing to use the modem part of the unit. Not so tru but it can be done, at least with my model.
Here is the trick: Disable DHCP, otherwise the router side of the modem is trying to hand out network addresses and this mucks up the whole process of multiple DHCP servers on your network handing out conflicting IP addresses.
This took me a couple hours to figure it out, I have to give credit to this forum postin on using a modem/router as an AP at dslreports.com (an awesome website by the way) specifically, this entry with step by step instructions. awesome
anyhow, on actiontec modems you will find the DHCP settings under the “ADVANCED” menu tab, picture below of what you are looking for (at least on my version)
By the way, this modem/wifi/router is terrible according to newegg reviews for many reasons. I should have never bought it but for wifi it seems to be okay. Among many gripes, there are security issues with ports being open if used as a modem.
Hope this helps someone, this is one of those posts I make just for my future personal reference to make wireless Ethernet bridges (as well as to burn it into my memory. If it helped you, drop me a comment – all are much appreciated!