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ASUS RT-N66U or wireless 900 Mbps


We have already seen an ASUS wireless router with similar design in our testing lab, but this is the first time we have ever come across a device that can transmit at 900 Mbps in the wireless segment. Such enormous speed is achieved by simultaneous transmission in each of the two wireless ranges (2.4 and 5 GHz). However, everything in its due course!

External design and hardware

The ASUS RT-N66U wireless router is performed in a black plastic case very similar to that we’ve already seen with RT-N56U, however, some things are different. The case dimensions are 207х149х36 mm and the ribbed surface is matte. In our view, such surface is less susceptible to scratching. For its operation RT-N66U requires a 19V and 1.58A external power adapter.

ASUS RT-N66U can be mounted on the wall or horizontally on the table or again on the table but vertically – with the help of a stand that is in the set. It seems to us that when RT-N66U is set vertically on the table it looks rather weird because of wires sticking up, but in general it’s quite decent. On the upper surface there’s an embossed vendor’s name and the device model as well nine LEDs indicating power supply and presence of devices connected to USB and status of five Gigabit Ethernet interfaces and two wireless ranges.

The front panel is featureless; the side ones have ventilation grates for better cooling electronic components.

On the bottom of RT-N66U there’s a sticker with brief information about the device, four rubber stands and two technological holes for mounting the router on the wall. A ventilation grate occupies most part of the device bottom.

On the rear panel there’re three removable antennas, the power button, the Reset and the WPS buttons, the latter simplifying connection of wireless devices; also, here’s a power slot, two USB 2.0 ports, one WAN and four LAN interfaces.

ASUS RT-N66U hardware is represented by one textolite board whose main elements are hidden under two metal screens. On the other side of the board you can only see a Spansion S29GL256P10TFI01 flash-memory module. To the screens on both sides of the board are attached metal radiators for increasing heat flow. Fortunately, just like in other ASUS models, RT-N66U doesn’t have an inside cooler, that is a system of passive cooling is employed.

On the board there’s also a slot with four pins for connecting a console cable, but unfortunately it is only intended for the vendor’s engineers. ASUS RT-N66U allows installing SD-cards inside the case, for which there’s a special slot on the board. Such installation doesn’t occupy external USB ports and is considered more reliable as it guarantees that the drive can’t be switched off accidentally. Unfortunately, force opening the case may void the warranty.

Now let’s have a look at the router software.

Firmware upgrade and utilities

Like for all other devices, for ASUS RT-N66U we advise to upgrade firmware to the latest available version. Firmware is upgraded with the help of the Firmware Upgrade tab in the Administration point. It can be done manually or automatically. In the manual mode the user has first to download the file with firmware from the site and then choose it on the page below and click Upload.

In the semi-automatic upgrade mode, the router goes to the vendor’s site by itself and downloads a new firmware version.

The whole upgrade process takes about three minutes (without the time for downloading the image) and doesn’t demand any special skills from the user.

Besides official firmware versions, there’s a whole range of alternative firmware. For instance, the DD-WRT team supports the ASUS RT-N66U wireless router. To install firmware, one has to perform the same actions as in manual upgrade of official firmware. The recommendations are the same – setting user configuration to default before and after the upgrade, and then – full manual configuration of the device. Moreover, one first has to upgrade to the “mini” version from which to jump to the fully functional version of the DD-WRT firmware. To be fair it has to be said that we failed to upload the dd-wrt.v24-18702_NEWD-2_K2.6_big_RT-N66U version: every time the router malfunctioned, though move to the dd-wrt.v24-18702_NEWD-2_K2.6_mini_RT-N66U version went without a hitch.

When firmware is being upgraded the router may become inoperative. To restore its firmware and settings, one has to run a special procedure. Firstly, RT-N66U has to be turned into the recovery mode, if it’s not there yet. One can see that the router is in this mode if the power indicator on the top panel is flashing slowly. To drive the device into the recovery mode, turn it off, press the Reset button and holding it pressed turn the router on again. After the power indicator starts flashing slowly, you can release the Reset button. Another sign that the router is in the recovery mode is TTL=100 in received ICMP echo-replies.

C:\>ping -t
Pinging with 32 bytes of data:
Reply from bytes=32 time<1ms TTL=100

Then you have to run the Firmware Restoration utility and specify the file with official firmware.

Besides a special utility, the administrator can access the router boot loader which also allows changing the malfunctioning firmware version via the web-interface of the boot loader.

Another way of recovery is to transmit a file with new firmware via TFTP.

C:\>tftp -i put c:\RT-N66U_3.0.0.3_108.trx
Successful transfer: 19226624 bytes in 14 sec., 1373330 bytes/s

If for some reason you still fail to boot, try one more trick – keep the WPS button pressed during booting. This will result in resetting user configuration and starting a wizard that will help to enter main parameters of RT-N66U operation.

Besides the Firmware Restoration utility, there’re two more of them in the set: Device Discovery and Router Setup Wizard. The former is intended for discovering ASUS wireless devices in the local net.

The latter – Router Setup Wizard – is for simplifying the process of connecting to the provider. This feature somewhat repeats the functions of the quick internet setup wizard of the router itself.

We have to confess that we were somewhat surprised that there’s no utility for configuring a remote multifunction device connected to RT-N66U. However, lack of such utility at the site is made up for by the possibility to download it by following a link in the Network Printer Server point of the USB application menu in the web-interface. Here there’re also links to detailed descriptions of the process of connecting a printing device.

We decided to use an external USB-drive for installing additional software. We have already described this process in much detail in the review devoted to the ASUS RT-N56U wireless router, so this time we’ll only have a glimpse of this issue; moreover, ASUS RT-N66U firmware already has everything needed. To get the list of packets ready to install, one should use the ipkg list command. The number of packets is so huge that we put the list into a separate file. Below as an example we present Dropbear installation – it’s an SSH protocol client and server; having done this we readily connected to RT-N66U via SSH.

admin@RT-N66U:/# ipkg install dropbear
Installing dropbear (0.52-5) to /opt/...
Installing psmisc (22.13-1) to /opt/...
Configuring dropbear
update-alternatives: Linking //opt/bin/scp to /opt/sbin/dropbearmulti
update-alternatives: Linking //opt/bin/ssh to /opt/sbin/dropbearmulti
Will output 1024 bit rsa secret key to '/opt/etc/dropbear/dropbear_rsa_host_key'
Generating key, this may take a while...
Public key portion is:
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgl6JwRE6BY4AtC3V8y3PN2RBhbVkIhhvxZhZRpVjbXEvvfSuyQDAh/KT9r1W6oV++7m5zdCfA1MmIsPz1fHh
jI/RJDMBKW3Z8xKIV3dFF08xMiyIZblgp5NF3WSa504xOEJ8wTqgowTp9lZJkEP5gCOD3ASPYW+vKohmXRJgRdT94fU= admin@RT-N66U
Fingerprint: md5 c2:92:0e:35:61:6d:8a:f4:f4:e0:e8:24:91:f2:49:62
Will output 1024 bit dss secret key to '/opt/etc/dropbear/dropbear_dss_host_key'
Generating key, this may take a while...
Public key portion is:
ssh-dss AAAAB3NzaC1kc3MAAACBAKf6QaSm6Mg1GMMqJ/EuAqLOaInhPY7rgDe3p6ESEpZXq9ueQJr3Gd4cfZREkjw1xsCjES66ASqW9fASnLk/9KFiCjUf
DTN4X0Flzbowaw+maw9NvbRHxtRmvfL41zK69dPWo+WUPjRD+wUIiEgYkTLlxMdShDd+cphrA9wkZUEaJ+t+oPCkGock8teMzNa8GRD00Qs= admin@RT-N66U
Fingerprint: md5 8b:fe:1b:55:c4:ad:ff:55:e1:de:fb:57:0c:15:3f:b2
Configuring psmisc
update-alternatives: Linking //opt/bin/killall to /opt/bin/psmisc-killall
update-alternatives: Linking //opt/bin/pidof to /opt/bin/psmisc-killall
Successfully terminated.
admin@RT-N66U:/# dropbear

Unfortunately, applications thus installed won’t start automatically after rebooting the router. We hope that the vendor will soon add this option when the users specify the scripts to run corresponding applications.

Here we’re through with the firmware upgrade and restoration process and with the utility set; now let’s move on to studying the router web-interface features.


We have waited for so long and at last we’ve got ASUS wireless router with the default firmware ASUS-WRT in our laboratory. To access the web-interface you need to address with the help of any modern browser. Login and password are default – admin/admin. Upon successful authentication the user finds himself on the start page where some brief information about the router and all the connected devices is shown. Web-interface RT-N66U is available in seventeen languages. ASUS RT-N66U supports both frequency ranges which work parameters are configured separately.

We won’t scrutinize all the functions of the web-interface but will get familiar with the most interesting items on the left menu. Luckily there are enough novelties.

The button “Quick Internet Setup” launches the router semi-automatic wizard to work on the provider’s network.

For each of two frequency ranges there can be created up to three guest wireless networks with the internet access or without it. Controlling these nets is possible via the button “Guest network” on the main menu.

The button “Traffic manager” is used to control the service parameters of the net in either manual or auto modes.

The button “Parental control” is implemented to restrict the access time of some definite hosts to the internet.

To control all the devices connected via USB is possible with the help of the “USB application” button. ASUS RT-N66U can play the role of file and media servers, print server, universal downloader and also it can back up the WAN-channel by using the 3G/WiMAX modems. We would like to pay special attention to the fact that the latest versions of the firmware allow using Download Master without installing any special software – all the management is accomplished through the web-interface.

Now let’s have a look at the items of the traditional menu on the left. The group “Wireless” is intended to set up the device work parameters in both frequency ranges. ASUS RT-N66U makes it possible to create wireless bridges with both 2.4 GHz devices and those ones that support the frequency of 5 GHz.

The settings of the local net can be found in the sub-items of the group “LAN”. With the help of this section you can control the IP-television consoles connection. The tab “Switch control” lets you configure some additional parameters of the switch chip’s work. One of such parameters is the jumbo-frame support and an opportunity to switch on and off the hardware accelerator.

The WAN group gives the administrator a chance to adjust the connection to a provider. The static and dynamic IP-addresses, PPPoE, PPTP and L2TP are supported. The tab “NAT Passthrough” enables configuring those tunnel protocols that are allowed to go through the device.

Wireless router ASUS RT-N66U with the default firmware supports IPv6. To find its settings you must address the same-name item.

Not less interesting and awaited is the function of the device to perform as a PPPTP-server, allowing the remote clients to connect to the router through the internet and get the access to local resources. All the settings mentioned are available in the section “VPN server”.

The sub-items of the group “Firewall” give the administrator an opportunity to manage the services which have internet access, the security from DoS-attacks and URL- filters.

Choice of the operation mode, firmware upgrade, restore/save/upload settings and also managing the system time can be done in the tabs of the group “Administration”.

We consider it a bit strange that the parameter “Remote Log Server” is situated here. It would be more logical to place this parameter in the next section connected with the device logs.

The last group not mentioned yet is the group “System Log” with the help of which you can get access to the logged information of the system itself, of the DHCP server, of the wireless router and to find out the ports being forwarded at the moment and the routing table.

This brings us to the end of the web-interface review, let’s learn the functions of the command line interface. The only thing that must be also mentioned is the introduction of RT-N66U wireless router web-interface emulator on the vendor’s site. Now everyone can distantly get acquainted with all the functions of the proposed device web-interface.

Command line interface

By default the access to the command line of the router is switched off. To switch it on you must address the tab “System” of the group “Administration”.

The access can be also performed in the old-fashioned way by addressing the hidden administrative page Main_AdmStatus_Content.asp where you should execute the command run_telnetd. Some similar approach we have already observed working with ASUS WL-330N3G wireless router, which review has once appeared on the site.

To access you are to use the same login and password as in the web-interface. ASUS RT-N66U wireless router has Linux operating system and BusyBox version 1.17.4.

admin@(none):/# busybox
BusyBox v1.17.4 (2012-03-08 19:28:37 CST) multi-call binary.
Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko
and others. Licensed under GPLv2.
See source distribution for full notice.
Usage: busybox [function] [arguments]...
or: function [arguments]...
BusyBox is a multi-call binary that combines many common Unix
utilities into a single executable.  Most people will create a
link to busybox for each function they wish to use and BusyBox
will act like whatever it was invoked as.
Currently defined functions:
[, [[, arp, arping, ash, awk, basename, blkid, cat, chmod, chown, chpasswd, clear, cmp, cp, crond, cut, date,
dd, df, dirname, dmesg, du, e2fsck, echo, egrep, env, ether-wake, expr, fdisk, fgrep, find, flock, free,
fsck.ext2, fsck.ext3, fsck.minix, fsync, ftpput, grep, gunzip, gzip, head, ifconfig, insmod, kill, killall,
klogd, less, ln, logger, login, ls, lsmod, lsusb, md5sum, mkdir, mkdosfs, mke2fs, mkfs.ext2, mkfs.ext3,
mkfs.vfat, mknod, mkswap, modprobe, more, mount, mv, nc, netstat, nice, nohup, nslookup, pidof, ping, ping6,
printf, ps, pscan, pwd, readlink, rm, rmdir, rmmod, route, sed, sendmail, setconsole, sh, sleep, sort, strings,
swapoff, swapon, sync, syslogd, tail, tar, telnet, telnetd, test, top, touch, tr, traceroute, traceroute6,
true, tune2fs, umount, uname, unzip, uptime, usleep, vconfig, vi, watch, wc, wget, which, zcat, zcip
admin@(none):/# uname -a
Linux (none) #1 Thu Mar 8 19:38:57 CST 2012 mips GNU/Linux

With the help of the command ps let’s have a look at the processes running at the moment.

admin@(none):/# ps
1 admin     1876 S    /sbin/init noinitrd
2 admin        0 SW<  [kthreadd]
3 admin        0 SWN  [ksoftirqd/0]
4 admin        0 SW<  [events/0]
5 admin        0 SW<  [khelper]
17 admin        0 SW<  [kblockd/0]
48 admin        0 SW   [pdflush]
49 admin        0 SW   [pdflush]
50 admin        0 SW<  [kswapd0]
51 admin        0 SW<  [aio/0]
95 admin        0 SW<  [mtdblockd]
112 admin        0 SW<  [kmmcd]
303 admin      608 S    hotplug2 --persistent --no-coldplug
348 admin     1864 S    console
349 admin     1540 S    /bin/sh
351 admin     1528 S    syslogd -m 0 -S -O /tmp/syslog.log -s 256 -l 7
353 admin     1528 S    /sbin/klogd
355 admin        0 SW<  [khubd]
429 admin     1872 S    usbled
464 admin        0 SW<  [scsi_eh_0]
465 admin        0 SW<  [usb-storage]
478 admin     1872 S    /sbin/wanduck
479 admin      624 S    udhcpc -i eth0 -p /var/run/ -s /tmp/udhcpc
485 admin      916 S    /bin/eapd
488 admin     1172 S    nas
493 nobody    1232 S    dnsmasq -c 1500 --log-async -n
494 admin     1548 S    httpd
495 admin      924 S    /usr/sbin/infosvr br0
496 admin      920 S    networkmap
498 admin     1872 S    watchdog
499 admin     1872 S    ots
500 admin     1872 S    phy_tempsense
502 admin      956 S    rstats
510 admin      988 S    lld2d br0
517 admin      744 S    miniupnpd -f /etc/upnp/config
518 admin     1944 S    u2ec
520 admin     1012 S    lpd
529 admin     1944 S    u2ec
530 admin     1944 S    u2ec
566 admin     1532 S    telnetd
572 admin     1552 S    -sh
585 admin     1532 R    ps

Let’s find out what files are located in the catalogues /bin, /sbin, /usr/bin/ and /usr/sbin. The top utility will display all the data on the running processes.

admin@(none):/# ls /bin
ash          cp           echo         gzip         mknod        nvram        rm           sleep        uname
busybox      date         egrep        kill         more         pidof        rmdir        sync         usleep
cat          dd           fgrep        ln           mount        ping         rstats       tar          vi
chmod        df           fsync        login        mv           ping6        sdparm       touch        watch
chown        dmesg        grep         ls           netstat      ps           sed          true         wps_monitor
comgt        eapd         gunzip       mkdir        nice         pwd          sh           umount       zcat
admin@(none):/# ls /sbin
ATE                         fsck.msdos                  mkswap                      setup_dnsmq
add_account                 fsck.vfat                   mod_account                 sigmon
add_folder                  get_account_list            mod_folder                  swapoff
add_multi_routes            get_all_folder              modify_if_exist_new_folder  swapon
arp                         get_apps_name               modprobe                    syslogd
asus_lp                     get_folder_list             mtd-erase                   tcpcheck
asus_sd                     get_permission              mtd-unlock                  test_disk1
asus_sg                     get_var_file_name           mtd-write                   test_disk2
asus_sr                     gpio                        ntp                         test_if_exist_account
asus_tty                    halt                        ots                         test_if_exist_share
asus_usb_interface          hotplug                     pc                          test_of_var_files
auto_macclone               hotplug2                    phy_tempsense               test_share
autodet                     how_many_layer              radio                       tune2fs
blkid                       ifconfig                    rc                          udevtrigger
console                     init                        rcheck                      usbled
create_if_no_var_files      initial_all_var_file        read_sms                    vconfig
ddns_updated                initial_folder_list         reboot                      wanduck
del_account                 initial_var_file            restart_wireless            watchdog
del_folder                  insmod                      rmmod                       wlcconnect
dhcp6c-state                klogd                       route                       wlcscan
dosfsck                     led                         run_app_script              wldist
e2fsck                      lsmod                       run_pptpd                   wpsfix
ejusb                       mkdosfs                     run_telnetd                 write_smb_conf
fdisk                       mke2fs                      send_sms                    zcip
fsck.ext2                   mkfs.ext2                   service
fsck.ext3                   mkfs.ext3                   set_permission
fsck.minix                  mkfs.vfat                   setconsole
admin@(none):/# ls /usr/bin
[            clear        env          free         logger       nslookup     sort         top          uptime
[[           cmp          ether-wake   ftpput       lsusb        printf       strings      tr           wc
arping       cut          expr         head         md5sum       pscan        tail         traceroute   wget
awk          dirname      find         killall      nc           readlink     telnet       traceroute6  which
basename     du           flock        less         nohup        smbpasswd    test         unzip
admin@(none):/# ls /usr/sbin             bcrelay               icon.ico              minidlna              tc   brctl                 icon.large.ico        miniupnpd             telnetd      chat                  igmpproxy             mt-daapd              u2ec  chkntfs               igs                   nas                   udhcpc     chpasswd              infosvr               networkmap            udhcpd            ip                    nmbd                  udpxy       crond                 ip6tables             ntpclient             usb_modeswitch      cru                   ip6tables-restore     pppd                  vsftpd       dhcp6c                iptables              pppoe-relay         dhcp6s                iptables-restore      pptpctrl       dnsmasq               l2tp-control          pptpd                 wl         ebtables              l2tpd                 radvd                 wlconf    emf                   lld2d                 scsi-start            wpa_cli           et                    lld2d.conf            scsi-stop             wpa_supplicant              lpd                   sendmail         ez-ipupdate           mDNSResponder         smbd        httpd                 madwimax              sysinfo
admin@(none):/# top
Mem: 37820K used, 217732K free, 0K shrd, 4128K buff, 11428K cached
CPU:   0% usr   0% sys   0% nic  99% idle   0% io   0% irq   0% sirq
Load average: 0.01 0.04 0.00 2/42 718
718   572 admin    R     1536   1%   0% top
518     1 admin    S     1944   1%   0% u2ec
530   529 admin    S     1944   1%   0% u2ec
529   518 admin    S     1944   1%   0% u2ec
1     0 admin    S     1876   1%   0% /sbin/init noinitrd
499   498 admin    S     1872   1%   0% ots
500     1 admin    S     1872   1%   0% phy_tempsense
498     1 admin    S     1872   1%   0% watchdog
478     1 admin    S     1872   1%   0% /sbin/wanduck
429     1 admin    S     1872   1%   0% usbled
348     1 admin    S     1864   1%   0% console
572   566 admin    S     1568   1%   0% -sh
494     1 admin    S     1548   1%   0% httpd
349   348 admin    S     1540   1%   0% /bin/sh
566     1 admin    S     1532   1%   0% telnetd
351     1 admin    S     1528   1%   0% syslogd -m 0 -S -O /tmp/syslog.log -s 256 -l 7
353     1 admin    S     1528   1%   0% /sbin/klogd
493     1 nobody   S     1232   0%   0% dnsmasq -c 1500 --log-async -n
488     1 admin    S     1172   0%   0% nas
520     1 admin    S     1012   0%   0% lpd
510     1 admin    S      988   0%   0% lld2d br0
502     1 admin    S      956   0%   0% rstats
495     1 admin    S      924   0%   0% /usr/sbin/infosvr br0
496     1 admin    S      920   0%   0% networkmap
485     1 admin    S      916   0%   0% /bin/eapd
517     1 admin    S      744   0%   0% miniupnpd -f /etc/upnp/config
479     1 admin    S      624   0%   0% udhcpc -i eth0 -p /var/run/ -s /tmp/udhcpc
303     1 admin    S      608   0%   0% hotplug2 --persistent --no-coldplug
95     2 admin    SW<      0   0%   0% [mtdblockd]
355     2 admin    SW<      0   0%   0% [khubd]
4     2 admin    SW<      0   0%   0% [events/0]
48     2 admin    SW       0   0%   0% [pdflush]
49     2 admin    SW       0   0%   0% [pdflush]
465     2 admin    SW<      0   0%   0% [usb-storage]
5     2 admin    SW<      0   0%   0% [khelper]
17     2 admin    SW<      0   0%   0% [kblockd/0]
464     2 admin    SW<      0   0%   0% [scsi_eh_0]
112     2 admin    SW<      0   0%   0% [kmmcd]
50     2 admin    SW<      0   0%   0% [kswapd0]
51     2 admin    SW<      0   0%   0% [aio/0]
2     0 admin    SW<      0   0%   0% [kthreadd]
3     2 admin    SWN      0   0%   0% [ksoftirqd/0]

The content of the catalogue /rom is pretty interesting. Well-known Oleg must have contributed to creation of this wireless router as well. So, much the better!

admin@(none):/# ls /rom
asus_base_apps.tgz                  libsigc++_2.2.3-1_mipsel.ipk        optware.oleg
downloadmaster_2.1.0.48_mipsel.ipk  libuclibc++_0.2.2-9_mipsel.ipk      pcre_8.30-1_mipsel.ipk
etc                                 libxml2_2.7.8-1_mipsel.ipk          spawn-fcgi_1.6.3-1_mipsel.ipk
libcurl_7.21.7-1_mipsel.ipk         ncurses_5.7-1_mipsel.ipk            zlib_1.2.5-1_mipsel.ipk
libevent_2.0.11-1_mipsel.ipk        openssl_0.9.7m-5_mipsel.ipk
libpar2_0.2-5_mipsel.ipk            optware.asus

Now let’s move to the catalogue /proc and see what files can be found here and get the information about the operating system uptime and its average load, learn the type of the CPU used and RAM capacity. In fact, the uptime and load information can be gained by means of the uptime system call.

admin@(none):/proc# ls
1              429            496            529            devices        kmsg           slabinfo
112            464            498            530            diskstats      loadavg        stat
17             465            499            566            driver         locks          swaps
2              478            5              572            execdomains    meminfo        sys
3              479            50             720            filesystems    misc           sysrq-trigger
303            48             500            95             fs             modules        sysvipc
348            485            502            buddyinfo      interrupts     mounts         timer_list
349            488            51             bus            iomem          mtd            tty
351            49             510            cmdline        ioports        net            uptime
353            493            517            cp0            irq            partitions     version
355            494            518            cpuinfo        kallsyms       scsi           vmstat
4              495            520            crypto         kcore          self           zoneinfo
admin@(none):/proc# cat uptime
7170.60 7157.68
admin@(none):/proc# cat loadavg
0.00 0.01 0.00 3/42 722
admin@(none):/proc# cat cpuinfo
system type             : Broadcom BCM5300 chip rev 1 pkg 0
processor               : 0
cpu model               : MIPS 74K V4.9
BogoMIPS                : 299.82
wait instruction        : no
microsecond timers      : yes
tlb_entries             : 64
extra interrupt vector  : no
hardware watchpoint     : yes
ASEs implemented        : mips16 dsp
shadow register sets    : 1
VCED exceptions         : not available
VCEI exceptions         : not available
unaligned_instructions  : 2
dcache hits             : 2147483648
dcache misses           : 2600203516
icache hits             : 2147483648
icache misses           : 4261409278
instructions            : 2147483648
admin@(none):/proc# cat meminfo
MemTotal:       255552 kB
MemFree:        217648 kB
Buffers:          4128 kB
Cached:          11428 kB
SwapCached:          0 kB
Active:           6852 kB
Inactive:        11068 kB
HighTotal:      131072 kB
HighFree:       112772 kB
LowTotal:       124480 kB
LowFree:        104876 kB
SwapTotal:           0 kB
SwapFree:            0 kB
Dirty:               0 kB
Writeback:           0 kB
AnonPages:        2372 kB
Mapped:           1648 kB
Slab:            14256 kB
SReclaimable:     3996 kB
SUnreclaim:      10260 kB
PageTables:        340 kB
NFS_Unstable:        0 kB
Bounce:              0 kB
CommitLimit:    127776 kB
Committed_AS:     6672 kB
VmallocTotal:  1015800 kB
VmallocUsed:      4800 kB
VmallocChunk:  1008924 kB
admin@(none):/proc# cd /
admin@(none):/# uptime
02:00:28 up  2:00, load average: 0.00, 0.00, 0.00

All the list of supported file systems and encryption type can be gotten from the following files: /proc/filesystems and /proc/crypto.

admin@(none):/# cat /proc/filesystems
nodev   sysfs
nodev   rootfs
nodev   bdev
nodev   proc
nodev   sockfs
nodev   pipefs
nodev   anon_inodefs
nodev   tmpfs
nodev   inotifyfs
nodev   configfs
nodev   devpts
nodev   ramfs
nodev   usbfs
admin@(none):/# cat /proc/crypto
name         : arc4
driver       : arc4-generic
module       : kernel
priority     : 0
refcnt       : 1
type         : cipher
blocksize    : 1
min keysize  : 1
max keysize  : 256
name         : sha1
driver       : sha1-generic
module       : kernel
priority     : 0
refcnt       : 1
type         : digest
blocksize    : 64
digestsize   : 20

The utility sysinfo from the catalogue /usr/sbin displays the detailed information about the device itself and its configurations. The output of this utility is presented in a separate file.

We can’t avoid mentioning the utility nvram that allows changing some important parameters of the device work.

admin@(none):/# nvram
usage: nvram [get name] [set name=value] [unset name] [show] [save file] [restore file]
admin@(none):/# nvram show | grep admin
size: 28469 bytes (4299 left)

Now it’s time we finished the command line interface review. Let’s pass over to testing.


Our first traditional test is to determine the wireless router booting time under which we mean the time interval between switching the power on and receiving the first echo reply via ICMP. ASUS RT-N66U boots within 17 seconds and we consider it an excellent result. During first ten seconds the router replies back several times but we don’t take it into account as the replies are gotten from the device boot-loader (TTL=100) but not from the real operating system.

Request timed out.
Request timed out.
Reply from bytes=32 time<1ms TTL=100
Reply from bytes=32 time<1ms TTL=100
Request timed out.
Request timed out.
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64

The next test was to check the security of the device via the utility Positive Technologies XSpider 7.7 (Demo build 3100). The scanning was performed from the LAN-segment. All in all there were twelve open ports detected: TCP-23 (Telnet), TCP-53 (DNS), UDP-53 (DNS), TCP-80 (HTTP), TCP-515 (Printer), TCP-3394 (d2k-tapestry2), TCP-3838 (Unavailable), TCP-5473 (unknown), TCP-9100 (Unavailable), TCP-9998 (Unavailable), TCP-18017 (HTTP) and TCP-44571 (HTTP). The most interesting findings are listed below.

As we have already mentioned in the web-interface section, the latest firmware versions for the model being tested contain the embedded utility Download Master that doesn’t need any installation of the control section on the users’ PCs. We decided to install this program on the router and launch the test file from the peer-to-peer network. Download Master update can run regardless of the firmware version. Obviously, if we connect some other medium to a USB, the installation and updating procedures are to be started again. It should be mentioned that Download Master can be controlled also with the help of the common utility Transmission Remote GUI.

We decided to check how much adequately the router with the firmware reacts to the fault disconnection of the USB-drive, for which we formatted the external USB disk into file systems EXT3 and NTFS. We must give ASUS RT-N66U credit and say that the disconnection and then the followed connection of the medium was processed successfully, but the second EXT3 connection can demand significant time to be checked after which the disk will become available. Moreover we want to mention that while using NTFS we saw the line with the error of input/output in the log, and the running downloads were supposed to be started again. Also when the drive was connected repetitively, all the active downloads were lost. We would recommend the user to place RT_N66U and the external disk in a way to avoid the flash-card accidental disconnection.

Apr 25 21:15:33 kernel: scsi 0:0:0:0: rejecting I/O to dead device

In the course of describing the hardware of the router we paid attention to the internal plug for micro SD cards. We couldn’t help placing the mentioned card in this slot. Since we didn’t have any spare micro SD, we took it from the Pocket Book 912 that was possessed by the editorial team. The card formatted into EXT3 file system we connected to our RT-N66U router and switched it on. On the main page of the device the information about the card used was missing, but among the mounted sections it could be found. All the card data were remotely available with the help of Samba.

admin@RT-N66U:/# mount
rootfs on / type rootfs (rw)
/dev/root on / type squashfs (ro)
proc on /proc type proc (rw)
tmpfs on /tmp type tmpfs (rw)
devfs on /dev type tmpfs (rw,noatime)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw)
usbfs on /proc/bus/usb type usbfs (rw)
/dev/sda on /tmp/mnt/BOOK type ext3 (rw,nodev,noatime,data=ordered)

Furthermore we decided to check the wireless router work in the DLNA-server mode for which we had downloaded some pictures and videos of our friend from his trip to Antarctica over the net. We had no problems while connecting with the device by means of Windows Media Player and the whole evening we spent watching the media from his travel.

Now let’s turn to the throughput test. All the main parameters of the testing stand are given in the table below.

Component PC Notebook
Motherboard ASUS Maximus IV Extreme-Z ASUS M60J
CPU Intel Core i7 2600K 3.4 GHz Intel Core i7 720QM 1.6 GHz
RAM DDR3 PC3-10700 Corsair 16 Gbyte DDR3 PC3-10700 Kingston 8 Gbyte
NIC Intel 82579V
Intel 82583V

Atheros AR8131
Atheros AR9285

Operating System Windows 7 x64 SP1 Rus Windows 7 x64 SP1 Rus

We decided to estimate the access speeds to the data located on the disk connected via for which we used the utility Intel NASPT version 1.7.1 using SMB connection. Before the test according to the Intel recommendations we had decreased the available RAM via the utility msconfig. The test results for all the three systems are presented below.

ASUS RT-N66U has a hardware NAT accelerator which can be enabled or disabled. We decided to test the speeds of the routing and transmission with the HWA switched on and off. The data transmission speeds for one, five and fifteen simultaneous TCP-sessions are shown below. Unfortunately, HWA can be implemented only for the sessions of address transmission, the simple routing is not affected by the HWA.

We couldn’t skip the router function of working with tunnels: ASUS RT-N66U can perform in both ways, as a client and as a server. On the diagrams below you can see the available bandwidth of each of the modes.

ASUS RT-N66U gives you an opportunity to work simultaneously in two wireless ranges of 2.4 and 5 GHz. For each range the maximum transmission speed in theory is 450 Mbps. We decided to find out the real speeds. For such a test we used the wireless adapter ASUS EA-N66 which had already been described. The results of the experiment for both ranges are shown on the diagram. At last we’ve managed to overcome the border of 200 Mbps!

This brings us to the end of the testing section. Let’s make conclusions.


The tested top model of the wireless routers ASUS RT-N66U has shown excellent data transmission speeds in the wired and wireless network segments. This model will let the user exploit the entire provided access to the internet.

All the strong points of the device are enumerated below.

  • Flexible configurations of the QoS.
  • High speeds of the USB-disk access.
  • Embedded PPTP server.
  • Stylish web-interface.
  • Possible internet use time restriction.
  • IPv6 support.
  • P2P network support.
  • Fast device booting.

Unfortunately, some drawbacks have been found as well.

  • Incomplete web-interface translation.
  • Significant web-interface inhibition with big load and with the HWA switched off.
  • Partial web-interface translation of the Download Master utility.
  • The case’s notable heating while being used, that doesn’t influence the work stability.

At the moment of writing the article the average price of ASUS RT-N66U wireless router in on-line shops of Moscow was 7000 rubles.