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Revision as of 02:53, 15 February 2007

Contents: 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
ReferencesExternal links


802.1x Extensible Authentication Protocol

(This entry needs your help.)


Channels 1 to 14 (depending on country) in the 2.4 GHz range. Supports transfers up to 11 megabits per second under ideal conditions. Longer range than 802.11g


Uses the same channels and 2.4 GHz frequency band of 802.11b. Supports transfers up to 54 megabits per second under ideal conditions. 802.11g equipment can typically operate in 802.11b mode when required to work in 802.11b environments. The equipment is newer and tends to have better receivers. Each channel tends to spread out by a couple of channels on either side. If a foreign channel is as strong as your signal, then you need to leave a gap of a couple of channels.


This is the 5.8GHz standard and is subject to more licencing restrictions than the above. The WRT54G is not capable of this, however since dd-wrt is available on hardware with mini-PCI slots these radios could be slotted in.


Access Restrictions

(This entry needs your help.)

Ad hoc

Ad hoc mode, one of the least popular modes, allows the router to connect to other wireless devices that are also available for ad hoc connections. Think of this mode as a Client Mode that doesn't connect to infrastructure networks but rather connects to other ad hoc-configured devices. (Think of an ad hoc network as a bunch of 8 year-olds without any adult supervision. Ad hoc networks lack the central management that is typical of an infrastructure type network.) Ad hoc mode doesn't use WDS but it does make use of STP.


Afterburner, also known as SpeedBooster, SuperSpeed, TurboG, 125mbps, HSP125, and G+ is a feature built into some routers that theoretically increase throughput through use of software, or firmware

Main article: Afterburner

Access Point

The default and probably the most common mode. The Access Point mode allows wireless clients to access the Internet, access each other wirelessly, or access other computers that may be connected to the switch with wires. A router in Access Point mode cannot connect wirelessly to other routers, but it can have other routers connected to it wirelessly as clients or repeaters. Access Point is the mode used when configuring a router to act as a repeater.


Boot Wait

Boot Wait is a feature you will hopefully never need. It introduces a short delay while booting (5 seconds). During this delay, you can initiate the download of a new firmware image if the one in the flash ROM is not broken. Obviously, this is only necessary if the installed firmware will not boot. The default and recommended setting is "Enable". You can access the Boot Wait setting by going to "Administration" > "Management".

Border Gateway Protocol

Border Gateway Protocol is the core routing protocol of the Internet, generally used by Internet Service Providers to establish routing between one another. It is also used on private networks to "multihome"


1. Improperly flashing one's WRT54G(S) in a way that renders it unusable
2. To cause to resemble a brick, in mode of operation as well as form
3. To render inert like a rock, or a brick, or ... well you get the general idea

See Also: Recover from a Bad Flash


Captive Portal

(This entry needs your help.)


Chillispot can be used for hotspot management. It requires a separate Web server to host the redirect URL and a separate radius server (these may be installed on the same machine, of course).

You can also use a hosted chillispot portal like which is free. It replaces both your radius server and your web server, and brings powerful features. You simply register there and create your hotspot. Then you can get the chillispot configuration settings to enter in the steps below, and you can get your hotspot working in some minutes.

Main Article: Chillispot


(This entry needs your help.)

Client Bridge Mode

Client Bridge mode is much like Client mode except the WLAN and the LAN are on the same subnet. Consequently, NAT is no longer used and services (such as DHCP) that are running on the original network will work seamlessly on the bridged network. Just like Client mode, a router in Client Bridge mode will not accept wireless clients and it will not broadcast beacons. (Note: A technical problem exists in Client Bridge mode. It appears that this mode is not a fully transparent bridge mode as MAC addresses that pass through the Client Bridged router from behind the Client Bridged router, get rewritten to the MAC address of the Client Bridged router. (Sorry, I couldn't think of a more confusing way to write it.) If you really need transparent bridging, consider using WDS Bridging instead.)

See Also: Wireless Bridge


(This entry needs your help.)

Client Mode

Client mode allows the router to connect to other access points as a client. In a nutshell, this turns the WLAN portion of your router into the WAN. In this mode, the router will no longer function as an Access Point (doesn't allow clients), therefore, you will need wires to use the router and to configure it. The router won't even be visible to your wireless configuration software or Wi-Fi sniffer software such as Netstumbler, since it no longer broadcasts beacons. In Client mode, the WLAN and the LAN will not be bridged, thus they will be on two different subnets. Port forwarding (from the WLAN to the LAN) will be necessary to make FTP servers, VNC servers, etc. that are located behind the Client mode router function properly. For this reason, most users chose to use Client Bridge mode instead of Client mode.

See Also: Client Mode Wireless

Connection Watchdog

This is a feature.


Normally called crontab, the cron subsystem is a type of scheduler for Unix/Linux that runs given commands at designated times. The default and the recommended setting is "enabled" since processes such as "Watchdog Scheduler" depend on it. You can access the Cron setting at "Administration" > "Management".



In Unix/Linux, a daemon (or dæmon) is a background process. Typically daemons have names that end with the letter "d"; for example, syslogd is the daemon which handles the system log.

Dynamic Host Control Protocol

DHCP is a set of rules used by a communications device (such as a computer, router or networking adapter) to allow client devices to request and obtain an Internet address from a server which has a list of addresses available for assignment. DHCP is also used to pass on DNS Server and Gateway information to DHCP clients. WRT devices generally include DHCP servers in their software suite.

Demilitarized Zone

A DMZ host is generally one selected device or computer on the network where all incoming traffic without a designated destination defined by PAT or Port forwarding, is forwarded to. Using a DMZ host is a lot like turning off the firewall capabilities inside your router and letting the DMZ host device handle all uninvited incoming traffic. For this reason, having a computer as a designated DMZ host can be a security hazard. DMZ is disabled by default in DD-WRT firmware. You can change DMZ settings by going to "Applications & Gaming" > "DMZ".

Domain Name

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Domain Name System

DNS Forwarder

Will forward any DNS request, to a DNS server of your choice (i.e. your ISP's); useful, for configuration/speed issues.

DNS Server

DNS Servers are the servers responsible for resolving names to IP addresses. When you point your browser to, a DNS Server has to resolve, (that is, look up the corresponding IP address) before the page is actually retrieved, since computers and networking equipment communicate using IP addresses instead of Domain Names. DNS Servers are built into routers, but they are only a local caching server that works in tandem with your LAN's DNS server(s) and/or your ISP's DNS servers.


(This entry needs your help.)

Dynamic DNS (DDNS)

Main article: Dynamic DNS

Dynamic DNS is a service that is hosted by a third party company. In order to take advantage of this service, devices (such as routers or computers) will require a client "updater" software to be installed to pass authentication and account information, and the network's current Internet IP address, in a timed manner. Many users want to be able to connect to another network (such as their home or office network) from another location but aren't able to connect unless they know the Internet IP address of that network. Because most ISPs provide IP addresses through DHCP (or charge extra for a static IP address) your IP address may change on occasion. Dynamic DNS is a system that allows you to match a domain name to your network's Internet IP address. Your Dynamic DNS updater software client will take care of passing the correct Internet IP address to centralized DNS servers on the Internet and will make sure it stays updated. So next time you want to connect to that network using VPN or Remote Access software you'll be able to use a domain name instead of trying to remember the IP address. Dynamic DNS services (such as will help you choose from a list of available domain names.



Ethernet is a large and diverse family of frame-based computer networking technologies for local area networks (LANs).

Extended Service Set Identifier

Sometimes called SSID. It's the tag broadcast by your access point and the one seen on site survey at the clients. It's what you have to associate with. As a rule you can only have one ESSID per Access Point, however it would be cool to have more than one, it would then look like you had several Access Points.

See Also: v24



Software or hardware that limits network activity


This is just Software but it runs on your Hardware. It's usually delivered as a binary ROM image that has to be copied down onto your hardware (WRT54G) over a cable. The cable is usually an Ethernet patch lead but could be a JTAG serial cable or doe some devices an RS232 cable. In the good old days we would burn an EPROM or FLASH chip in a programmer and then insert the chip physically into a socket. Hence the term Firmware being software you can touch in the form of a chip.



Setting the operating mode to "Gateway" allows your router to route packets between the LAN/WLAN and the Internet (through the WAN port). This is the default setting and the most common setting when the router is hosting the network's Internet connection through the WAN port



Host is a generic term used when referring to a computer or device that is hosting a specific service or acting as some type of server. For example, if you have a mesh network in place, the "host" router would probably be the one hosting the Internet connection

Host Name

(This entry needs your help.)


A location where Wireless Internet has been provided for people to use. An example of this would be to switch on your laptop in a cafe and associate with the ESSID available there, perhaps CAFE-HOTSPOT. Attempting to view a Web site would show the Hotspot landing page where you could press a button for free access or create an account and pay by card. This depends on the operator of the Hotspot. Once in, you can simply use the Internet normally

HTTP Redirect

This option enables an HTTP Redirector for proxy usage

Main article: HTTPRedirect


A large Hotspot, perhaps covering a whole town



Institute of Electrical and Electronics Engineers — a professional organization for electrical and electronics engineers hosting a number of special interest societies and standards committees. The IEEE is responsible for creation of standards such as IEEE 802.11.


a network adapter

See Also:


Internet Protocol version 6 — an extension of Internet Protocol version 4 (IPv4). IPv4 uses an address space of 32 bits, allowing it to support 232 (about 4.3×109) addresses. IPv6 uses an address space of 128 bits, allowing it to support 2128 addresses; this is approximately 5×1028 addresses for each of the roughly 6.5×109 people alive today.

Internet Service Provider

An Internet service provider (abbr. ISP, also called Internet access provider or IAP) is a business or organization that sells to consumers access to the Internet and related services.


Journalling Flash File System (JFFS)


A JTAG cable is a cable that hooks up to a JTAG interface, such as those on Linksys routers. It allows you to communicate with the router using your computer's parallel port. In many cases, a JTAG cable is an invaluable component used to debrick a partially or completely bricked (but not dead) router.



The Kai console Daemon (kaid) is a service that provides tunneling for console games that do not have an inherent connection to the Internet. Although the label refers to XBOX, the daemon works well with PS2, and Gamecube consoles as well. It also allows the new Sony Playstation Portable (PSP) to go online with some of their multiplayer wireless games.


Kismet is a layer 2 wireless network detector, sniffer, and intrusion detection software that runs on Linux.

See Also: Kismet Server/Drone


Local Area Network

Local Area Network, or LAN, is your router's switch ports and your router's wireless interface have been bridged into one LAN. Most references in the forums and the Wiki are using the term LAN in this manner, although you may need to adjust your thinking according to the context it's used it. For example, the LAN on a WRT in Client mode is only the wired switch ports, because the wireless portion is acting a WAN interface.


Loopback is a problem that occurs when multiple routes exist to the same destination. This can happen when a router is connected to an ad hoc network or is configured to function in a mesh network with several WDS-enabled routers. See STP


MAC Address

Media Access Control
A MAC address is a unique identifier attached to a network interface. It is stored in hexadecimal and usually appears in the following format: 00:00:00:00:00:00 or 00-00-00-00-00-00

MAC Filtering

A method of filtering which devices can or cannot connect to a WRT by storing corresponding MAC addresses. MAC filtering is generally only performed on the wireless interface of a WRT.

MAC Number

Migration Authorisation Code number. Not to be confused with MAC Address. This is the number your ADSL ISP gives you when you want to switch to another ISP without a long wait whilst the phone company sends out engineers to move the wires. As you can imagine, this number can be held to ransom until you pay the old ISP bill, which is, of course, a contravention of the Ofcom guidelines

Mesh Network


Network Address Translation

NAT (Network Address Translation) is the translation of an Internet Protocol address (IP address) used within one network to a different IP address known within another network. One network is designated the inside network and the other is the outside. Typically, a company maps its local inside network addresses to one or more global outside IP addresses and unmaps the global IP addresses on incoming packets back into local IP addresses. This helps ensure security since each outgoing or incoming request must go through a translation process that also offers the opportunity to qualify or authenticate the request or match it to a previous request. NAT also conserves on the number of global IP addresses that a company needs and it lets the company use a single IP address in its communication with the world.


In the world of DD-WRT and Linksys routers, a neutered router is a v5 or v6 router that has reduced RAM and reduced flash memory, in comparison to other supported devices, thus the name neutered.


NoCat originally started as a community-supported 802.11b wireless network in Sonoma County, CA and has grown into several projects whose purpose is to encourage the building of wireless community networks.

NoCatAuth is the original "catch and release" wireless captive portal implementation. It provides a simple splash screen web page for clients on the network, as well as a variety of authenticated modes.

Also see:

Noise Reference

"noise reference is just for calculating snr in ap mode and nothing else. so just cosmetic."

Source: A posting by BrainSlayer on the Google-cached LinksysInfo forums


The NVRAM is a portion of your router called Non-Volatile RAM. Your configuration/settings are stored in the nvram.

N Connector

This is the "good old" and "pro" type of antenna cabling connectors used for economical cabling and third-party high-gain antennas, RG-213 or LMR-400 cabling, cable television, and military uses ;). Converters can be used between these and RP-TNC and RP-SMA connections. Has nothing specifically to do with wireless N.

See also: Connector Photos Wikipedia



(This entry needs your help.)

Open Shortest Path First

One of several router protocols known as IGPs, (Interior Gateway Protocol). Using OSPF, a host that obtains a change to a routing table or detects a change in the network will immediately multicast the information to all other hosts in the network so that all will have the same routing table information. This method is more efficient than RIP (Routing Information Protocol) which sends the entire routing table to a neighboring host every 30 seconds. OSPF also uses more advanced algorithms to determine the shortest path, where RIP1 and RIP2 simply use hop counts. If your router is acting as a repeater, OSPF is the recommended protocol to use unless your network has other devices that only support RIP2.


Port Forwarding

Port Forwarding is necessary to allow computers outside of the LAN to access services that may be hosted by one or more computers inside the LAN. Since there is a shortage of public IP addresses in IPv4, the issue was conquered using NAT. While NAT isn't all bad (it adds security) it does introduce some complications when a computer inside an LAN is hosting a public service such as a web server, ftp server, or e-mail server. Port forwarding was designed to take care of this problem. Port forwarding can be configured in DD-WRT by going to "Applications & Gaming" > "Port Forwarding". You can also forward ranges of ports instead of single ports by going to "Applications & Gaming" > "Port Range Forwarding". Routers can be configured to listen on one port but forward to a different port. While it isn't foolproof, this can add a measure of security by using obscure ports to listen instead of the default ports that attackers expect you to host common services on.

Port Triggering

(This entry needs your help.)

Point-to-Point Protocol over Ethernet (PPPoE)


(Point-to-Point Tunneling Protocol)



(Quality of Service)
Main article: Quality of Service



Linux IPv6 Router Advertisement Daemon

The router advertisement daemon (radvd) is run by Linux or BSD systems acting as IPv6 routers. It sends Router Advertisement messages, specified by RFC 2461, to a local Ethernet LAN periodically and when requested by a node sending a Router Solicitation message. These messages are required for IPv6 stateless autoconfiguration.

Also see: Litech's information on radvd,Linux HQ's information on radvd


While repeater is not a selection in the "Wireless Mode" drop-down menu, it is commonly thought of as a mode that is different from the others listed above. In reality, a router acting as a repeater is configured as an Access Point (AP Mode) and has WDS (Wireless Distribution System) enabled. To use your router as a repeater will also require you to enable and configure WDS in the router you are connecting to (the "host router"). Do not attempt to turn on repeater mode by using the "Site Survey" and then the "Join" button to connect to other routers, as this will actually put your router into Client mode. Also, be aware that using your router as a repeater will reduce the router's wireless throughput since WDS uses wireless bandwidth that would normally be available to wireless clients, to "talk" to other routers. This reduction in wireless bandwidth will probably not be noticeable if the repeater router(s) are used only to share an Internet connection, unless you have more than three routers "daisy-chained" in this manner.

See Also: WDS Linked router network


(This entry needs your help.)


(Routing Information Protocol )
RIP1 and RIP2 are both older protocols that are to be used only when an existing network does not have OSPF compliant equipment. In short, RIP2 is slightly more secure and slightly more efficient than RIP1, while OSPF has great advantages over both. It is assumed that RIP2 is in the feature set primarily for backward compatibility reasons.


See: WRT

RP-SMA Connector

A Reverse Polarity SubMiniature version A Connector is a type of antenna connector used on brands of routers including Buffalo and ASUS. Also found on PCI cards.

See also: Connector Photos Wikipedia N Connector

RP-TNC Connector

A Reverse Polarity Threaded Neill-Concelman Connector is a type of antenna connector used on Linksys access points. Designed to make it difficult to add high-gain antennas which breach FCC rules!

See also: Connector Photos Wikipedia N Connector


Abbreviation for receive or receiver



A free software re-implementation of SMB/CIFS networking protocol in Linux and most UNIX-like systems, allowing Microsoft Windows machines to access files and printers on a Linux or UNIX host over a network.


The Simple Network Management Protocol (SNMP) is an application layer protocol that facilitates the exchange of management information between network devices. It is part of the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. SNMP enables network administrators to manage network performance, find and solve network problems, and plan for network growth.

Two versions of SNMP exist: SNMP version 1 (SNMPv1) and SNMP version 2 (SNMPv2). Both versions have a number of features in common, but SNMPv2 offers enhancements, such as additional protocol operations. Standardization of yet another version of SNMP — SNMP Version 3 (SNMPv3) — is pending. This chapter provides descriptions of the SNMPv1 and SNMPv2 protocol operations.

Source Code

This is the software before cross-compilation into firmware. For firmware this is usually written in C. For dd-wrt the source can be downloaded and cross-compiled on the PC to produce firmware that is ready to be downloaded onto the WRT54G. This is not something most people need to do since the compiled binary firmware is usually available.

Secure Shell

SSH clients can access information and make changes to remote systems that are running an SSH server. Telnet or SSH can be used as another method of changing settings on your DD-WRT router, as opposed to the Web Interface. Certain changes to your DD-WRT router can only be done using Telnet or SSH. More Info on using Telnet/SSH


SIPatH is a configurable, free and RFC3261-compliant SIP proxy. SIPatH features a Status web interface, enables individual VoIP provider settings on each IP phone and internal calls among all registered phones within the local network. Main projects objectives are providing a simple solution of the SIP-over-NAT problem and free PBX-like telephony features. According to the last release notes, other features included:

  • NAT-RTP proxying and improved SIP-NAT traversal
  • Aliases for registered URIs, configurable at runtime via a web interface
  • SIP Messaging: Messages can be sent through the web interface to all registered SIP UAs

The SIPatH project is now being continued by the Boozy version of the router software maintained by Milkfish project.

Static DHCP

An extension of the DHCP protocol enabling the server to issue a specific IP address to a client based on its MAC address. This feature effectively guarentees that the client will receive the same IP every time it requests a new lease, yet the configuration is dynamic in all other respects.


(Spanning Tree Protocol)
STP needs to be enabled to prevent loopbacks on networks where multiple paths to the same point are possible. A mesh network that uses multiple repeaters where repeaters have WDS configured to work with more than one device should enable STP. STP is known to interfere with the router's DHCP client for users who use Comcast Cable as their ISP.

Main article: Spanning Tree Protocol



Telnet clients can access information and make changes to remote systems that are running a Telnet server. SSH is similar to Telnet and is preferred because Telnet traffic is not encrypted, thus usernames and passwords are passed in plain text and can easily be sniffed by packet sniffing software. Telnet or SSH can be used as another method of changing settings on your DD-WRT router, as opposed to the Web Interface. Certain changes to your DD-WRT router can only be done using Telnet or SSH. More Info on using Telnet/SSH


Abbreviation for transmit or transmitter


Universal Plug-n-Play

Universal Wireless Repeater



(Virtual Local Area Network)
A VLAN is, in basic terms, a group of physical interfaces on a switch that behave as if they are a separate standalone switch. While using one physical switch, a VLAN allows you to partition it into multiple LANs, each one completely isolated from the others. The switch must support VLAN configurations — most cheap switches don't allow this, but high-end manageable switches do, as does the internal switch on DD-WRT compatible routers.


(Voice over Internet Protocol)
VoIP is a rather new technology for making phone calls using the Internet. Skype is an example of VoIP, but so is Vonage, which allows you to use a real phone directly plugged into your WRT54G rather than needing to fire up your PC.


(Virtual Private Network)
A VPN allows two LANs together over the Internet using a virtual cable, or VPN. You have PPTP, IPSec, OpenVPN. Mostly dd-wrt is not too good at doing this but will allow these service to operate as a pass-through. Hence the term VPN-Passthrough.

VPN Passthrough

The router allows you to run a VPN service on your network. The VPN version of dd-wrt has this.

VPN Server

This is where the router actually creates a VPN connection to another VPN server. This is the one you really want for VPN. The VPN version of dd-wrt does not seem to do this.


Wide Area Network

Wide area network, also referred to as WAN, deals with


The act of scanning for wireless networks and hotspots whilst traveling. See also Wombling.


(Wireless Distribution System)
A Wireless Distribution System is a system that enables the interconnection of access points wirelessly. In DD-WRT, WDS allows multiple WRTs to communicate with each other wirelessly without the need for a wired backbone. A WRT communicating in this manner is generally referred to as a repeater.

WDS Bridging

WDS Bridging is when you setup a repeater router to "talk" to a main/host router and then disable the Access Point function in the repeater so that it will not accept clients. You'll need to run a short script from the shell to achieve this. A WDS Bridge is fully transparent. In this configuration the wireless portion of the repeater WRT has bridged the repeater WRT's LAN interface with another WDS enabled wireless device. WDS Bridging is done in Access Point mode.

Main article: WDS Bridging


Wireless Internet Service Provider — a company using wireless gear such as WRT54G and dd-wrt to deliver Broadband Internet into peoples' homes without using their phone line. The advantage of a WISP is that one is not limited by the speed of one's telephone line and perhaps one doesn't even have a telephone line at the service location. Since there is no telephone line, the WISP is not paying fees to the telephone company, so can often provide a better service at the same cost. You could start your own WISP or at least a hotspot with your dd-wrt.


(Wireless Local Area Network)


Wake-on-LAN is an Ethernet computer networking standard that allows a shut-down computer to be booted remotely. The network card of the computer that has WOL enabled will listen for a "Magic Packet", then verify the information in that packet and decide whether or not to boot the computer.


Also known as Wardriving, wombling is the act of scanning for wireless networks and hotspots whilst traveling. This was traditionally done with a Proxim ORiNOCO PCMCIA card in a laptop with a Pringles can Yagi antenna. We are talking old school. The connection with the Wombles comes from "Orinoco" who is, of course, one of the Wombles from Wimbledon Common. It is often thought that using someone's Internet connection without their permission is illegal. It seems to be a form of trespass, so if you don't look at any local files or break anything then you're probably OK. However if you bring their connection into disrepute or slow it down significantly or look at their personal files then you are clearly a bandit and could get prosecuted. If they have taken trouble to secure the connection then you should respect that and not break past the security.


(Wireless Receiver/Transceiver)