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DDWRT on Asus RT-AC66U


DDWRT router


Here in Holland the hype to get fiber to home is booming. Unfortunately where I live Cable is still the fastest connection available with 200 Mbit download and 20 Mbit/s upload speed, the standard
modem that is packed with this provider (which is actually an Cisco EPC3928AD with a “Ziggo” skin”) is missing a lot of features and most of all WiFi signal strength.


What’s in the box

So I bought a router that I could Supercharge with DDWRT! This is a Linux based alternative OpenSource firmware with a lot of functionality. Just a few examples why I decided for DDWRT;

  1. Remote access your network with [OpenVPN],
  2. Better Firwall than regular routers [iptables]
  3. Advanced Quality of Service (QoS)
  4. DNS control behind the firewall (DNSmasq)

The website behind DDWRT (http://www.dd-wrt.com) has an extensive list of routers they support. You can not supercharge just any router. They have to meet a certain requirement like amount of RAM available etc. Based on my budget (below  €150,-), three adjustable antenna’s , Dual Band (2.4/ 5 GHz) with minimal 2 antennas. I ended up with the [Asus RT-AC66U] which was also in the “supported routers” from a DDWRT perspective.

[The Installation]

    1. Asus_RT-AC66U_Clean_Setup

      Clean setup

      I like to setup a clean environment and NOT losing my internet connection so I downloaded the Firmware (dd-wrt-Asus_RT-AC66U.trx 17,5 MB) first and made sure I had putty working for a telnet connection. Because I had nothing attached to my laptop, as you can see in the photo, I got an IP address from the modem and was able to browse to the default IP from the router (

    2. We need to clear the “NVRAM” which is only be done by command line. We therefor need to enable “Telnet” to access the command line. Open your favorite web browser (mine is Chrome) and go to the home of the new router. If this is the first time you powered on the router, you need to walk thru the setup. You can select “Skip Setup Wizzard” and hit “Apply”, ignore all messages and hit “next”. Once you see the normal menu go to the “system” panel in the “Administration” menu. There you will find the “Enable Telnet” radio button. Once you select “Yes” Hit apply.
    3. Next is to login using telnet. I love to use Putty though most modern operating systems have “telnet” pre-installed. If you want to check run “cmd” (Command Prompt) en type [telnet] if telnet is installed it will ask for a username and password. If not, and you get an error, use Putty and make sure you select “telnet” to We need to enter the following command to clear the NVRAM and perform an reboot afterwards. Once you are logged in (default username and password are both “admin”), enter the following command [mtd-erase -d nvram]Below is my complete command line output
      ASUSWRT RT-AC66U_3.0.0.4 Tue Dec 16 08:38:40 UTC 2014
      admin@RT-AC66U:/tmp/home/root# mtd-erase -d nvram
      Erasing 0x0 - 0xffff
      "nvram" successfully erased.
      admin@RT-AC66U:/tmp/home/root# reboot


    4. Asus_RT-AC66U_Upload_FWThis will reboot our modem but still having the original Asus Firmware active. Now that we have the NVRAM cleared we can continue with the actual installation. Once the system is rebooted login again on and, again, skip the setup wizard. Navigate again to “Administration” but this time select “Firmware Upgrade“. Use the “Choose File” to navigate to the download we did in step 1. Once you chosen the file (make sure its the correct one like show in the screen-shot), hit “Upload”. This can take several minutes (it took 2 at my place) and you will see a message with “upload complete, please manually reboot”. I powered off and On and after 1 minute the new dd-wrt firmware webpage was shown. You have to create a username and password
    5. We need to clear the NVRAM once more time though, also in dd-wrt by default, telnet is disabled. Navigate to Administration > Management > Remote Access > Telnet Management and hit the radio button “enable”, leave the default port and connect again using putty.  Please do note that the default user on the command line is always “root” with the same password you just created.  Once logged in use the command [mtd -r erase nvram] once more. DD-WRT will reboot automatically. Below is my CLI output.
      DD-WRT login: root
      ==========================================================____ ___ __ ______ _____ ____ _ _
      | _ \| _ \ \ \ / / _ \_ _| __ _|___ \| || |
      || | || ||____\ \ /\ / /| |_) || | \ \ / / __) | || |_
      ||_| ||_||_____\ V V / | _ | | \ V / / __/|__ _|
      |___/|___/ \_/\_/ |_| \_\|_| \_/ |_____| |_|DD-WRT v24-sp2
      BusyBox v1.21.0 (2013-03-25 11:33:45 CET) built-in shell (ash)
      Enter 'help' for a list of built-in commands.
      root@DD-WRT:~# mtd -r erase nvram
      Unlocking nvram ...
      Erasing nvram ...
      admin@RT-AC66U:/tmp/home/root# reboot


    6. After the reboot we have to, again, create a username and password. That’s it that’s all! Connect the WAN port (the blue one next to the USB ports) from your new super charged router to the existing internet connection and your good to go. I’ve used a yellow cable between my Ziggo Modem and my DD-WRT router as you can see in the photo below. The red cable is going to my switch where some PC’s and camera’s are hooked up to. During the next few weeks I will setup openVPN and show you how you can connect to your home network.




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