Asuswrt-Merlin - custom firmware for Asus routers

Asuswrt is the router firmware developed by Asus, and which they use on all their recent models.

Asuswrt-Merlin (this project) is a customized version that I am developing, and includes various improvements and fixes over the original Asuswrt.


Asuswrt-merlin is available for the following routers:

  • RT-N16
  • RT-N66U
  • RT-AC66U
  • RT-AC56U
  • RT-AC68U
  • RT-AC68P
  • RT-AC87

(note: the U, R and W variants are all supported, as they are the exact same hardware and firmware, only different marketing SKUs or different case color)


Notable features (over the original firmware):

  • Based on the source release from Asus
  • Various bugfixes (like the crash on VPN/NAT Loopback access of LAN devices)
  • Some components were updated to their latest versions, for improved stability and security
  • Persistent JFFS partition
  • User scripts that run on specific events
  • Cron jobs
  • Customized config files for router services
  • LED control - put your Dark Knight in Stealth Mode by turning off all LEDs
  • Entware easy setup script (a modern alternative to Optware)
  • SNMP support
Disk sharing:
  • Optionally use shorter share names (folder name only)
  • Disk spindown after user-configurable inactivity timeout
  • NFS Exporting of USB drives
  • Better compatibility with 3TB+ and Advanced Format HDDs


  • Act as a Master Browser
  • Act as a WINS server
  • SSHD
  • Allows tweaking TCP/UDP connection tracking timeouts
  • CIFS client support (for mounting remote SMB share on the router)
  • Layer7 iptables matching
  • User-defined options for WAN DHCP queries (required by some ISPs)
  • Improved NAT loopback (based on code from phuzi0n from the DD-WRT forums)
  • Advanced OpenVPN client and server, based on code originally written by Keith Moyer for Tomato and reused with his permission. (RT-N66U, RT-AC66U, RT-AC56U, RT-AC68U)
  • Netfilter ipset module, for efficient blacklist implementation
  • Site survey page (under Wireless)
  • Configurable min/max UPNP ports
  • IPSec kernel support
  • DNS-based Filtering, can be applied globally or per client
Web interface:
  • Improved client list, with DHCP hostnames
  • Optionally save traffic stats to disk (USB or JFFS partition)
  • Enhanced traffic monitoring: added monthly, as well as per IP monitoring
  • Name field on the DHCP reservation list and Wireless ACL list
  • System info summary page
  • Wireless client IP, hostname, rate and rssi on the Wireless Log page
  • Wifi icon reports the state of both radios
  • Display the Ethernet port states
  • The various MAC/IP selection pulldowns will also display hostnames when possible instead of just NetBIOS names
  • Wireless site survey
A few features that first debuted in Asuswrt-Merlin have since been integrated/enabled in the official firmware:
  • 64K NVRAM (RT-N66U)
  • Turning WPS button into a radio on/off toggle
  • Clicking on the MAC address of an unidentified client will do a lookup in the OUI database.
  • WakeOnLan web interface (with user-entered preset targets)
  • Display active/tracked network connections
  • VPN Status page
  • DualWAN and Repeater mode (while it was still under development by Asus)
  • Basic OpenVPN (client and server) support
  • Configurable IPv6 firewall




The primary goal of this custom firmware is to tweak, fix bugs, and enhance the original Asus firmware.  It is NOT meant to become a feature-laden alternative - for that look at existing solutions, such as Tomato or DD-WRT, both offering a wealth of additional features.

To install, just flash this like a regular firmware update.   If coming from a different version, it's often best to reset to default settings after flashing this custom build.

Make sure you read the included README for instructions regarding these additional features.




Source code: