Firmware FAQ

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WEP is known to be easily cracked, so use Disabled and don't fool yourself into thinking you are secure. WEP is known to be easily cracked, so use Disabled and don't fool yourself into thinking you are secure.
-= Links =+=See also=
-*<b>[[Configuration_HOWTOs|How-To's]]</b>&nbsp;&mdash; Many Walk-Throughs for Different DD-WRT Configurations+* [[Tutorials]]</b>&nbsp;&mdash; Many Walk-Throughs for Different DD-WRT Configurations
-*<b>[[Glossary]]</b>&nbsp;&mdash; Wireless Networking Terms and Definitions along with DD-WRT Feature explanations+* [[Glossary]]</b>&nbsp;&mdash; Wireless Networking Terms and Definitions along with DD-WRT Feature explanations
 +=External links=
 +* [ DD-WRT homepage]
[[Category:English documentation]] [[Category:English documentation]]
[[Category:Indexes]] [[Category:Indexes]]

Revision as of 20:07, 17 February 2007


Before install

Is my router supported?

We have a page in the Wiki just for you. Supported Devices

I have a Linksys WRT54G version 5 or 6 router.

We have a page in the Wiki just for you. Version 5 And 6 Router Information

Which router should I buy?

In short, the Buffalo WHR G54s is the cheapest 100% compatible wireless router. For more information see Supported Devices

Where do I download firmware? See here to know which image download

What's the difference between generic, mini, micro DD-WRT versions?

See this

How do I access the router's settings?

If you have DD-WRT installed, your router's settings should be accessible by opening a web browser and typing in the address bar. If you have changed the LAN IP address on the router, you'll need to type in the correct one instead. If your router doesn't have DD-WRT installed yet, try or or else consult the manufacturer's documentation. Whether you have DD-WRT installed or not, make sure your computer has an IP address in the same scheme as the router. Try pinging the router to make sure you have connectivity. Try accessing the settings using a network cable instead of accessing them wirelessly. Try clearing your browser's cache. If you've been messing with proxy settings, make sure you didn't leave some incorrect proxy settings in your browser. And last but not least, try holding the reset button in for 30 seconds. It will reset all your settings back to defaults, but it should let you back into the router. Also see the Wiki article on the Web Interface

During install

How can I tell if my router is truly bricked?

Since this question involves many variables, we do not have an article for it yet. Try a hard reset. See: Reset And Reboot.

If the power light flashes on and off, then the firmware is messed up, but the router should be recoverable. The CPU must be running in order for the power light to be flashing, which tells you the hardware is probably not toasted yet. To test this, give your computer a static IP address of 192.168.1.x where x is between 2 and 254. Set the subnet mask to Then ping If you get replies, then your router is not dead.

Also, try pinging the router while it is booting. If you're able to get a reply for a short time, you should be able to reflash the firmware while the router is booting.

I think I've bricked my router!

There's a lot of variables in answering this question and we don't have articles to cover all the different situations. But, for now, search the Wiki and the forums for more information, just to verify that it's truly bricked. Try a hard reset. See Reset And Reboot. Then see: Recovering from a bad flash.

How do I install DD-WRT firmware?

Make sure you have a compatible router. Make sure you follow all the instructions, especially the part about resetting your router before flashing and in between each additional flash. See Installation

Why has http stopped working on my router after flashing DD-WRT?

Never forget to reset your router to Factory Defaults before AND after flashing the firmware. See also Reset And Reboot. Also make sure you are on the same subnet as your router. Your router's IP address is probably and make sure your computer is set to dynamically receive his address or set statically to 192.168.1.xx. If your computers IP address is you may not be able to access the interface.

What Are Firmware or Factory Defaults?

DD-WRT firmware default settings (sometimes called factory defaults) are stored in NVRAM. For more information, see Factory Defaults.

How do I upgrade my firmware with TFTP?

Flashing with TFTP must not be seen as the standard procedure for flashing: only use it when you are specifically told to do so (for example in the specific instructions for flashing your brand or type of device). Normally, the GUI flashing method should be used; it should be perfectly adequate for any standard situation. See Installation

Debricking for Asus WL-500G Deluxe

Debricking Asus WL-500G Deluxe after unsuccesfull DD-WRT flash or Corrupted NVRAM.

This guide applies ONLY when WL-500G Deluxe does NOT respond to the normal ASUS firmware restoration tool! (See your Driver CD for the utility)

Step 1: Download this restoration firmware was made by OLEG from . Rename it to nvram.trx!

Step 2: Download latest firmware from, rename it rom.trx

Step 3: Open your router by taking off the rubber nobs on the bottom, then unscrew the 4 screws.

Step 4: Configure your NIC with the IP make sure that it is in 10MB half duplex mode!

Step 5: Look for a small chip called 29lv320 and shor PIN 10 with the golden wireless plug using a paperclip. The router will show the powerlight blinking and one of your LAN interfaces should come active. Sometimes shorting PIN 9 and 10 at the same time helps..

Step 6: Ping If no response go to step 5 and try again.

Step 7: Open the commandshell of windows and type: tftp -i PUT nvram.trx, and wait 5 min. Reboot your router and do step 5 again.

Step 8: Open command shell and type: tftp -i PUT rom.trx, and wait 5 min. Reboot your router, it should show you Power, Air and connected LAN interface.

Step 9: Praise the lord, and pass the ammonition. You just did an emergency flash recovery of your WL-500G DELUXE. GUIDE by: Thomas Motshagen ©

After install

What's the default username and password?

Starting with v23 SP1, the default username is root and the default password is admin. You can use http/telnet/ssh to login.

I upgraded from early SP2 to a recent version, why does my login no longer work?

In current versions the http_passwd is no longer stored in plaintext. So you old password does not match anymore. Mostly you can still telnet in and try

~ # nvram set http_passwd=""
~ # nvram commit
nvram_commit(): end
~ # 

but it is strictly recommend to do a reset of the nvram.

Why does my router hang when using P2P applications? (BitTorrent, eMule,...)

You probably need a little tuning. We have a page in the Wiki just for you: Router Slowdown

Why can't I obtain an IP address from the WAN side via DHCP?

  • Unplug the router and cable modem. Plug in the cable modem first and wait until it is online. Plug in your router. Helped?
  • Next thing to try: Clone the MAC address from the old router/computer. Some ISPs have a MAC address registered for service on their end. Since these ISPs usually assign only one dynamic address at a time, you may need to release the IP assigned to the old router/computer to allow the DD-WRT router to get a new one.
    • Now you may have an option to click the DHCP Release button and then turn off the MAC cloning.
  • See Reset And Reboot (v23sp1 after upgrade from stock Linksys WRT54G v1.1)

Why can't I access the web configuration for my router?

If you've read the previous question and it didn't help, then your router's HTTP Daemon might not be running. See hard reset The other problem that currently causes this is incorrect HTTP Redirector settings, found at "Administration" > "Hotspot". By default the HTTP Redirector is disabled. If you enabled the HTTP Redirector and you suspect you might have created a problem, see the fix on this page: HTTPRedirect

Why do I only get blank pages when I try to change foobar in the webif and hit apply?

Obviously you did not do the 30sec Reset AFTER flashing DD-WRT: Reset And Reboot. Or try using a different Browser, clear the browser cache + cookies and stuff like it...

Why can't I save any changes after flashing to DD-WRT?

Obviously you did not do the 30sec Reset AFTER flashing DD-WRT: Reset And Reboot. Or try using a different Browser, clear the browser cache + cookies and stuff like it...

How do I clear the NVRAM?

See: Reset And Reboot.

How do I reset to factory defaults or firmware defaults?

See: Reset And Reboot.

How do I perform a cold reboot?

See: Reset And Reboot.

How do I get the Internet to work on my router?

"After upgrading to DD-WRT, my Internet doesn't work anymore." A common problem for which there is no single common fix. Understanding networking, subnets, NAT, etc. would be in your best interests to troubleshoot this issue. For DSL users, generally PPPoE is the best option. You may need to call your Internet Service Provider (ISP) for settings that are particular to your connection. Some ISPs expect the MAC address of your modem to be communicating with their servers so you may need to use the "Clone MAC Address" feature. Make sure you use the correct username and password. For cable and satellite users, generally DHCP is the correct setting. For Comcast Cable users, be sure to disable STP. For users trying to share a dial-up connection, you'll need to read the Wiki article Sharing Dialup. At any rate, it's a near 99% chance that the problem is not your DD-WRT firmware, but instead your lack of understanding with networking.

Why aren't DHCP-served IP addresses on LAN sequential (100, 101, ...)?

This is normal. DD-WRT uses DNSMasq and does not give sequentially ordered IP addresses. The addresses are calculated based on your computer's MAC address and "a variable". It's just a little different from the way the original Linksys firmware worked. You can disable this behavior by disabling "Use DNSMasq for DHCP" in the Basic Setup page (although it is not recommended, as you would need to change also your DNS address). For those who want the details about DHCP variable, it's calculated using something like [lease_start + [[mac_hash + variable] % lease_max]]. The "variable" changes whenever DNSMasq sees a conflict.

Why is there no jffs-space left? Why can't I write to directories other than /tmp?

Why are LAN computers not shown in local DHCP table, but are able to use network?

The lease table is cleared when the router is upgraded, unplugged, rebooted, and in situations where a config change requires a reboot. If your computer is already connected when this happens, it will remain connected but will not be in the lease table until the next time it tries to renew. You can disable this by enabling "Use NVRAM for client lease DB" on the Services page. This will store the lease database in the NVRAM.

Wireless questions

I'm having lots of TX (transmit) errors.

Try setting the ACK Timing to 0. If you have the transmit power turned up higher than 84 mW, turn it down to 84 mW. Other things that may contribute to a lower error rate: set beacon interval lower than the default of 100 (75, for example), use a different channel (aka frequency) for wireless (so not to clash with other 2.4 GHz devices). Use a better antenna that the stock antenna your device comes with, this actually helps you more than increasing ouput power as this option increases both ouput and sensitivity at the same time.

How high should I set the transmit power on my router?

Somewhere around 84 mW is considered to be the best setting for maximum power with minimum noise for most hardware. The Buffalo WHR-HP-G54 has a built-in amplifier. If the amplifier is turned on, the radio power should not be set above 10 mW. The forums have had discussions about what power level is safe, with little consensus. Use common sense and don't set the power higher than you really need to. If you're trying to get more range, consider using a different antenna and make sure you have a clear line of sight, two of the most critical factors in your router's range.

From a network security standpoint, the transmitter power level should be just enough to cover the intended area reliably. Optimal power settings can be determined by trial-and-error.

How can I increase my wireless range?

Many factors affect your range. What method you use to extend your range will depend on whether you are trying to increase the range inside a building or outside. Read the next two FAQ's below.

Consider getting a good antenna and try setting up your wireless devices with a clear line of sight. Best range is achieved by using one directional parabolic dish or Yagi antenna and then disabling the other antenna on your router. For situations where you need omnidirectional distance instead of directional linking, be sure to use a good omnidirectional antenna and mount it high enough to broadcast signal in the are of focus. This is often 20 to 50 feet high, depending on the rated signal downturn of the antenna.

Also, try increasing your router's transmit power to 84 mW (unless you have a Buffalo with a built-in amplifier). DD-WRT also has settings for frame burst and afterburner. You may see an increase in range by turning these off. If you are mostly interested in Internet access then 802.11b (as opposed to 802.11g) has longer range and may actually give you faster Internet speeds in long-range, low-signal situations. (Be aware that you cannot use "802.11b Only" mode with WDS. If you're using WDS and WPA encryption, you must use "802.11g Only" mode.)

How can I increase range indoors?

Some buildings do not allow your signal to pass through very well. The usual reason for this is foil-clad plasterboard or insulation. In an effort to insulate buildings and keep heat in, new plasterboard is foil clad to reflect infrared energy back into the room. However this means you effectively have huge metal sheets stopping all radio waves, so mobile phones, baby monitors, audio radios, and WiFi will all have problems with signal. Doors and windows usually allow wireless to pass through nearly unaffected, so positioning your antennas so the signal lines up through these openings will help. Also, you need to consider using a proper CAT5 cable between the points since the speed and reliability of this is far better. If you need wireless coverage, consider using more than one Access Point but wire them with network cable rather than attempting WDS repeater mode. Also, the WRT54G has a number of excellent 9 dB and 12 dB RP-TNC antennas available on eBay.

For transmission between floors, remember that the signal radiates away perpendicular 90 degrees from the antenna. This means that you can angle your signals up or down simply by angling the antennas, ideally so that both devices' antennas face each other on the same plane. For example, to broadcast directly upwards, point the length of the antennas used flat down. Also, on dual antenna routers, you can have one angled for upstairs and one for downstairs on the same device thereby giving each floor a targeted signal.

How can I increase range outdoors?

The most important thing for making your signal go far outside is height! The higher in the building you position your radio the further its signal will travel. Even a standard indoor unit with standard antennas can be used from 600 m away! To go farther you need to start using better antennas, the Access Point would work well with a 7 dB mounted just above roof height, this will give you a good 600 m to 1500 m, it goes further in open areas and less far in built up areas. It's important to match the gain and height of your antenna to how far away you wish to receive your signal. You may end up picking up signals that you would be better off not being able to see. Also the use of too much height with a 12 dB antenna would mean your signal does not really come back to ground level for several kilometers past where you wish to use it. The effect of this is that it seems your signal is weak and does not go very far. This is an illusion: The signal could be going way over your head. A lesser gain antenna at a lower height would yield a far stronger local signal and immunity for interference from far away stray signals.

How do I read signal and noise ratings?

These numbers are given in decibels (dB) and are expressed as negative numbers. So, a lesser number, like -10 dB, represents more strength than -70 dB. The values are logarithmic. A signal amplitude change of 3 dB is equivalent to a factor of two; 10 dB is a factor of ten.

Based on this Forum-post

Signal -> Low is good (well -10 is good, -98 is bad, mathematically -10 is higher than -98.)

Noise -> High is good (-98 is good, -10 is bad, -70 would be pretty bad in the real world)

SNR -> High is good (should be the same as difference between noise and signal, a difference of 20 would be great, a difference of 1 may barely work)

Signal Quality -> High is good (somewhat like SNR but indexed to 100 with noise as the base, percentage of the best theoretical available quality in regards to your local-noise, difficult to explain *g*)

Examples would be:

    Signal  Noise  SNR  Signal Quality
   -82     -98    16   14%
    Signal - Noise = SNR
   -82    - -98   = 16
   Signal/Noise * SNR = Signal Quality
   -82   / -98  * 16  = 13.4%

Typically, noise will be -92 which means you should get a connection with a signal as low as -92. However, expecting to hold a good connection with a signal less than -85 (e.g. -90), is expecting too much. The signal can be improved by -3 dB by doubling the power setting at the transmitting radio, e.g., 100 mW increased to 200 mW would improve your signal from -85 to -82. Antennas with increased gain will also help. Say you had the standard 3 dB antenna and changed it for a 12 dB antenna, that's a 9 dB increase, so your signal would increase from -82 to -73 which would be an excellent signal, probably capable of 54 Mbps. Using the term excellent in terms of running a WISP, it would probably be only 3 bars on a 5 bar signal strength meter. Don't worry if, as a WISP your signal quality is low, like 14%. It's not really a problem since -82 is considered acceptable.

What Wireless Security settings should I use at home?

For home or small network use you probably don't have a RADIUS server ("enterprise"), so will be using pre-shared keys ("personal"), which use a common passphrase for the network.

Make sure your passphrase is sufficiently complex, e.g. at least five random words (such as from diceware).

The wireless security settings, in decreasing order of preference, should be the pre-shared key versions of the following:

  1. WPA2 + AES
  2. WPA + AES (only if all devices support it).
  3. WPA + TKIP
  4. Disabled (no security)

If your network includes a RADIUS server, you can use the RADIUS versions of the above.

WPA2 Mixed tries to fall back from WPA2 to WPA; similarly AES+TKIP tries to fall back as necessary. These may help support a mixed environment, but your ultimate security will be the lowest level.

WEP is known to be easily cracked, so use Disabled and don't fool yourself into thinking you are secure.

See also

  • Tutorials</b> — Many Walk-Throughs for Different DD-WRT Configurations
  • Glossary</b> — Wireless Networking Terms and Definitions along with DD-WRT Feature explanations

External links

  • [ DD-WRT homepage]