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Wireless Reviews

Left: ASUSWRT -Merlin firmware, Right: Standard ASUSWRT firmware
Left: ASUSWRT -Merlin firmware, Right: Standard ASUSWRT firmware


I used to drink the alternative firmware Kool-Aid. My first experience with alternative firmware was running MRBios on my old Gateway 2000 P5-120 just because it was there. At the time, I felt MRBios was more stable and gave me more features. Then again, that was during the days of Windows 95 and extraordinary instability, so anything could have been perceived as improvement.

I never ran any benchmarks to prove anything to myself and probably wouldn't have believed them if I did. I just knew different had to be better and the original manufacturer had to be keeping me from using my system to its fullest potential.

When DD-WRT started getting popular, I was lucky enough to have a Linksys WRT54G lying around. I still remember the article Hack Attack: Turn your $60 router into a $600 router, which sounded great to me! After reading up on the upgrade process, I loaded it right up—possible bricking be damned! While DD-WRT included a plethora of features, the reality was that I hardly used any of them beyond amplifying my wireless signal, which didn't seem to help throughput much.

It wasn't until I read the two SmallNetBuilder articles,Can DD-WRT or Tomato Fix Bad Routing? and Lots More Features, Lots Less Performance: NETGEAR WNR3500L with DD-WRT Reviewed that I really started to objectively question my own thinking as to whether different was necessarily better or simply just different.

At that time, I had progressed to a Buffalo WZR-HPG300N, which Buffalo offered with its own firmware and with a Buffalo-branded DD-WRT firmware. Aesthetically, the Buffalo firmware was a pig in a dress, i.e. items were confusing, pages weren't laid out as you'd expect them and it just plain looked bad.

In contrast, the DD-WRT interface looked polished and consistent so you just knew it had to be better. Flashing back and forth however, I noticed the Buffalo firmware had more consistent wireless performance. The nail in the coffin for the Buffalo firmware, however, was its lack of support for NAT loopback. I was doing web development at the time and needed to access webservers on my lan by their FQDN. Buffalo's firmware did not support NAT loopback, but the DD-WRT rebrand did.

When Tim asked me to take a look at the ASUSWRT-Merlin firmware for the popular ASUS RT-N66U Dark Knight, I'll admit I was skeptical. This firmware is the brainchild of Eric Sauvageau, who goes by RMerlin in the SNB forums. What I found was a refreshingly different focus from other "alternative" firmware. Here is Eric's project description from the forum sticky.

The primary goals of this project are to fix bugs, add a few basic features and tweaks to the original firmware. This firmware will try to remain as close as possible to the original firmware. If you are looking for a slew of advanced features, then this project is not for you. Look at TomatoUSB or DD-WRT, two excellent products that might suit your needs better.

If however you prefer something as close as possible to the manufacturer's firmware, then this is for you.

The ASUSWRT-Merlin firmware, rather than reinventing the wheel and flashing your router to something completely different, simply expands upon the original manufacturers code. In some cases he fixes bugs, sometimes completes features, or occasionally adds features not present in ASUS' firmware. In reading through release notes, it appears ASUS has even provided Eric with beta code to test and work with. So the underlying code in ASUSWRT-Merlin is still ASUS', which should theoretically give you the best of both worlds.

For the sake of brevity, I'll be referring to ASUSWRT-Merlin as simply "Merlin" for the rest of this review.

Re-examining the ASUS firmware

Before diving into Merlin, I wanted to go back through the original Dark Knight review and take a look at what Tim reported as some of the missing or broken features to see if ASUS had fixed them.

I upgraded the router to ASUS' latest firmware and found that many shortcomings had indeed been fixed. One example is the DLNA media server. While not functioning in the original review, I found it to work pretty well in the latest firmware. The one exception being that the USB drive disappeared sporadically. Reboots of the router wouldn't fix it; I needed to pull the USB drive and reinsert it to have the drive functional again.

The grammatical "Enabled" buttons in the Guest Network settings to enable a guest network are now simply "Enable" as they should be. NAT loopback also works now as I was able to acess local hosts by their internet FQDN. Remote administration of the router now has HTTPS and IP access lists. I believe this first appeared in Eric's Merlin firmware and later in the ASUS firmware.

Parental controls now have a keyword, URL and Network Services filters. However, these controls are under Firewall and not Parental Controls. The controls also are global settings, i.e. not settable per client.So if you want to block your pre-teen from using Facebook, it will unfortunately be blocked for everyone.

Not fixed are the QoS settings and the lack of alarms on the Traffic Monitor.

Merlin Feature Summary

I tested the Dark Knight with the latest Merlin release, According to the SmallNetBuilder forums sticky, Merlin provides the following changes over the original firmware:

  • WakeOnLan web interface (with user-entered preset targets)
  • JFFS persistent partition
  • User scripts executed at init, services startup, WAN up, firewall up and shutdown.
  • SSHD (through dropbear)
  • OUI (MAC address) lookup if you click on a MAC on the Client list (ported from DD-WRT)
  • Saving your traffic history to disk (USB or JFFS)
  • Displaying monthly traffic history
  • Cron jobs
  • Monitor your router's temperature (under Administration -> Performance Tuning)
  • Display active/tracked network connections
  • Allows tweaking TCP/UDP connection tracking timeouts
  • Various bugfixes: crash issues related to VPN, etc...
  • layer7 and cifs kernel modules added
  • Optional user-settings for the WAN DHCP client (required by some ISPs)
  • Description field added to DHCP reservation entries
  • Dual WAN support (RT-N66U, RT-AC66U)
  • Disk spindown after user-configurable inactivity timeout
  • System info summary page
  • Wireless client IP, hostname, rate and rssi on the Wireless Log page
  • OpenVPN client and server, based on code originally written by Keith Moyer for Tomato and reused with his permission. (RT-N66U, RT-AC66U)
  • Customized config files for router services
  • Customized config files for router services
  • LED control - put your Dark Knight in Stealth Mode by turning off all LEDs
  • Option to force your router in becoming the SMB master browser

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Over In The Forums

  • Asuswrt-Merlin 378.51 Beta 1 is out" class="lightTip" target="_self" rel="nofollow">Asuswrt-Merlin 378.51 Beta 1 is out
    Highlights of this release:

    • Official support for the RT-N16 is being dropped. This last model based on SDK5 requires too much efforts to maintain. New features such as the new wireless log would have to be re-written specifically for that model.
    • The RT-AC3200 is now supported.
    • Entware is now supported on ARM models, based on Zyxmon's Qnapware repository
    • Completely redesigned the Wireless Log page. With the addition of a third radio on the...

    Asuswrt-Merlin 378.51 Beta 1 is out
  • ASUS RT-AC87 Firmware - Official Releases" class="lightTip" target="_self" rel="nofollow">ASUS RT-AC87 Firmware - Official Releases
    Good Day,
    The official first public release - - is now or will shortly be available for update via the Firmware Upgrade option under the Administration tab. Most of the US servers now offer the upgrade and the balance of North America and other regions will have the update available by tomorrow. The support site will be updated by Monday.

    I will post stable betas in this thread as they become available.


    Update 12/17/2014 - Beta...

    ASUS RT-AC87 Firmware - Official Releases
  • Setting a random password for guest wifi


    edit : following comments on this thread, I have added a couple of alternate functions that provide different ways of creating a random password. getrandopenssl uses the openssl rand option,...

    Setting a random password for guest wifi" class="lightTip" target="_self" rel="nofollow">Setting a random password for guest wifi
    I was going to post this directly here, but I must have too many code tags so it wouldn't let me.

    As such, I have posted on the wiki on how to do this :

    Setting a random password for guest wifi


    edit : following comments on this thread, I have added a couple of alternate functions that provide different ways of creating a random password. getrandopenssl uses the openssl rand option,...

    Setting a random password for guest wifi
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    RT-N66U micro sd card slot.


    Got it working somehow.

    The card was labeled as microSDHC UHS-I 32GB.

    My old cardreader did not accept it,
    so I had to ssh into the RT-N66U and fdisk and format it as ext2.

    At least I can now ftp to it and see some folders I created.

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    I can not get Download Manager to install.
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    Site Survey does not find any WLAN networks (on AC68U)" class="lightTip" target="_self" rel="nofollow">Site Survey does not find any WLAN networks (on AC68U)

    Since long time (actually I reported this issue already on firmware 374.40) the Site Survey does not find any WLAN network (on my AC68U).

    The manual execution of the apscan.asp returns an empty list:
    On my N66U...

    Site Survey does not find any WLAN networks (on AC68U)