BridgeChecker v1.3 Beta Available for Download

BridgeChecker is a windows utility that can automatically disable/enable wireless interfaces. Whenever your computer is connected to an Ethernet port and the link state is good, the utility can automatically turns off the IEEE 802.11 wireless network interface. This conserves IP address allocation, reduces security risks, resolves dual interface routing issues, and prolongs battery life.

Please read the BridgeChecker User Guide before installing and using BridgeChecker v1.3 beta.

BridgeChecker v1.3 has several new features that are summarized below.

BridgeChecker v1.3 Adds Location Awareness

BridgeChecker v1.2 has two modes, BridgeChecker Mode and OneNIC Mode. BridgeChecker v1.3 adds a Location Mode for enabling and disabling adapters based on the client location being “Work” or “Remote”.

To determine if the client’s location is work or remote the administrator can use a ping test, URL test, or gateway IP check. Based on the results of the test the adapters selected for Work or Remote location will be enabled and all other non whitelisted adapters will be disabled. The test will be rechecked every 1, 2, 3, 4, or 5 minutes with 5 minutes being the default check interval.

Location Ping Check

Location URL Check

Location Gateway IP Check

BridgeChecker v1.3 Adds Service Startup Delay

v1.3 adds the ability to delay the start of the BridgeChecker service during the boot cycle. This feature is accessed via Manage Settings screen and can be set to 0, 1, 2, 3, 4, or 5 minutes. The default setting is zero minutes delay.

BridgeChecker Service In “Starting” Status During Delay Period

BridgeChecker Service In “Started” Status After Delay Period Ends

BridgeChecker v1.3 Adds Support for x64 Bit Operating Systems

BridgeChecker now supports x64 Windows Vista and Windows 7. If you previously experienced the error message below, BridgeChecker v1.3 solves this issue.

System.InvalidOperationException: The ‘Microsoft.Jet.OLEDB.4.0′ provider is not registered on the local machine.
at System.Data.OleDb.OleDbServicesWrapper.GetDataSource(OleDbConnectionString constr, DataSourceWrapper& datasrcWrapper)
at System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection)

The program runs in 32 bit mode and installs in the Program Files (x86) directory. Make sure to install by running setup.exe as administrator.

BridgeChecker v1.3 Beta Download

BridgeChecker v1.3 Beta Download. (offsite)

BridgeChecker v1.3 Beta Bug Report and Feedback

Please use comment form below to send in bug reports or feedback regarding BridgeChecker v1.3 Beta.

BridgeChecker Mailing List

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Locally Administered MAC Address

The Locally Administered MAC Address is used to override the “burned-in” address of network interface cards (NICs). The Locally Administered MAC Address is a user-defined MAC address that is used in place of the MAC address originally assigned to the network adapter. Every adapter in the network must have its own unique MAC address. This locally administered address consists of a 12-digit hexadecimal number.

The appropriate assigned ranges and exceptions for the locally administered address include the following:

The range is 00:00:00:00:00:01 to FF:FF:FF:FF:FF:FD.
Do not use a multicast address (least significant bit of the high byte = 1).
Do not use all 0s or all F’s.

Creating An Access Point With A Locally Administered MAC Address

Using airbase-ng we can create an Access Point with a locally administered MAC address.

root@bt:~# airbase-ng -e “SSID” -a 00:00:00:00:00:01 wlan0
For information, no action required: Using gettimeofday() instead of /dev/rtc
16:37:27 Created tap interface at0
16:37:27 Trying to set MTU on at0 to 1500
16:37:27 Access Point with BSSID 00:00:00:00:00:01 started.

Tools Used To Create Virtual Access Point

BackTrack 4 beta VM Image
Netgear WG111US Wireless G Usb Adapter

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How Does Airplane WiFi Work?

Airplane WiFi works like WiFi at free WiFi at coffee shops and book stores. The main components of an airplane WiFi system are below.

1. Computer/WiFi enabled device (laptop, iPhone)
2. Airplane WiFi network (access points)
3. Air-to-ground wireless data connection (satellite or EVDO)
4. Ground Internet service provider

The technology to make the entire system work is transparent travelers. All that is required is an 802.11 WiFi enabled device and a method to pay for the service. WiFi on airplanes is available on most major airlines.

Airplane WiFi Configurations

There are two companies, GoGo Internet and Row 44, that most airlines are using to provide airplane WiFi service. GoGo Internet uses a ground based cellular data network for data communications and Row 44 uses satellite communications.

Row 44 Airplane WiFi

Satellite antenna atop of plane to communicate with satellites and other electronics inside cabin.

Row 44 Airplane WiFi Equipment

Southwest Airplane Row 44 Satellite Antenna

Row 44 Airplane WiFi Service

GoGo Inflight Airplane WiFi Configuration

GoGo’s airplane wifi configuration is similar to Row 44 except that they rely on a ground based EVDO network (like cell phone data networks) for communications to airplanes.

GoGo Aircell Airplane WiFi EVDO Network

Aircell Airplane WiFi Equipment

GoGo Internet Airplane WiFi Service

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Airplane WiFi Wireless Internet Update

Since my previous post about airplane wifi, a few more airlines have launched wifi Internet using either Aircell’s GoGo or Row 44’s service.

A quick review of the two technologies is below.

Aircell’s GoGo Airplane Internet Service

Aircell has been authorized by the FAA and FCC to use cellular frequencies for inflight broadband communications. Based on a tech primer by Aircell from March 2007 the network is summarized below.

• 100 or fewer EVDO antennas across the US providing coast-to-coast coverage.
• AirCell broadband uses an EV-DO (Rev. A) air-to-ground link, which provides peak data rates up to 3.1Mbps from the ground to the airplane, and up to 1.8Mbps from the airplane to the ground.
• Usable Internet access but not high speed Internet as expected by users with 30Mbps Internet access at home.

Language from tech primer below acknowledging speed limitations of network architecture and GoGo service.

AirCell broadband will be fast enough to give you complete, unfettered access to the Internet without excessive load times. It will run regular e-mail programs with normal attachments just like you do on the ground. It’s not as fast as a T1 line feeding a large corporation, but in daily operations very few people would notice a difference in download times between the two – and then, only when working with very large files. Participants that have demonstrated prototypes of the system in flight have been extremely happy with their experience.

Row 44’s Airplane Internet Service

Unlike Aircell, who built a wireless network for inflight WiFi Internet, Row 44 purchases bandwidth from HughesNet. Bandwidth can be very high, much higher than the EVDO based network used by Aircell but HughesNet uses geosynchronous satellites (about 42,164 km from Earth) has always suffered from latency issues when used for two-way communications. Additional details from Row 44’s website about the broadband system are below.

• Data rates averaging 30 Mbps in the downlink direction (from the satellite to the aircraft) and 620 Kbps maximum in the uplink direction.
• System will allow full access to the Internet as well as VoIP services, cell phone roaming usage where allowed by government regulation as well as live TV using IPTV.
• The system weighs less than 150 lbs and can be installed in two overnights, with the plane re-entering revenue service between the overnights.
• Second multi-cast 45 Mbps receive-only channel can be provisioned using the same equipment for dedicated transport of IP television. The passenger will gain access to all these services via the airline’s in-flight entertainment system or their own devices through Wi-Fi access points onboard the aircraft.

In-Flight WiFi Guide

Below is a summary compiled by travel site Jaunted with prices and WiFi Internet services offered by major airlines.

Filed under: WLAN/WiFi News | no comments yet, your thoughts are welcome

DoD Commercial WLAN Technologies Instruction 8420.01

The US Department of Defense (DOD) released a commercial wireless local area network (WLAN) devices, systems, and technologies Instruction (NUMBER 8420.01) that implements the DoD Directive 8100.2 related to commercial wireless that was released in 2004 and updated in 2006 [DoD Instruction Number 8420.01].

DoDD 8100.2

Use of Commercial Wireless Devices, Services, and Technologies in the Department of Defense (DoD) Global Information Grid (GIG) – April 14, 2004. [source]

DoDD 8100.2 Supplement

Use of Commercial Wireless Local-Area Network (WLAN) Devices, Systems, Technologies in the Department of Defense (DoD) Global Information Grid (GIG) -June 2, 2006. [source]

The 8420.01 Instruction mainly applies to DoD owned 802.11 devices and networks.

The Instruction does not apply to non 802.11 technologies such as Bluetooth and WIMAX and non DoD systems that use 802.11 such as hotspots, hotel, and home networks.

Policy for Unclassified WLANs

Unclassified WLAN systems shall be standards-based and IEEE 802.11 compliant, employ certified RF communications functions for interoperability, and employ certified and/or validated information assurance (IA) and cryptographic functions.

Unclassified WLAN-enabled PEDs shall use antivirus software, personal firewalls, data-at-rest encryption, and implement strong identification and authentication (I&A) (e.g., two factor, at a minimum) to access the device and the network.

PED = Portable Electronic Device (aka PDA, PDA phone)
WLAN-enabled PEDs = Devices like the iPhone, Palm Pre, and newer Blackberry smartphones

Policy for Classified WLANs

Employ National Security Agency (NSA)-approved encryption end-to-end and secure the storage, processing, receipt, and transmission of information accessed using NSA-approved encryption.

The WLAN must include information assurance measures:

• Classified WLAN-enabled PEDs shall use NSA, Type 1 encryption to protect classified data-in-transit and data-at-rest on PEDs.
• Unclassified and classified DoD wired and wireless LANs shall have a wireless intrusion detection capability that can be used to monitor WLAN activity and identify WLAN-related policy violations.
• Unclassified and classified WLAN-enabled PEDs used to access DoD e-mail systems shall support the signing and encrypting of e-mail.

Download DoD WLAN Instruction 8420.01 PDF

Download and read the entire DoD Instruction Number 8420.01.

Filed under: WLAN Policy, WLAN Security | no comments yet, your thoughts are welcome

Mac OS X Wireless Problems

I have fewer issues when running Windows XP on my Mac hardware using bootcamp compared to Mac OS X so I know the hardware is OK. Below are several troubleshooting techniques I use when I have connectivity issues.

First, confirm you have the latest airport client software! The Mac OS X Snow Leopard 10.6.2 AirPort client update is suppose to fix the following issues.

This update is recommended for all Macintosh computers running Mac OS X Snow Leopard 10.6.2 and includes fixes for the following:

• Inability to turn AirPort on or off in some cases after upgrading from Mac OS X Leopard
• An occasional loss of network connection when using Wake on Demand
• Inability to create a computer-to-computer network, or share the Internet connection on some MacBook, MacBook Pro, and Mac mini computers

Troubleshooting Mac OS X Wireless

I applied the Mac OS X Snow Leopard 10.6.2 AirPort client update a few days ago but still have occasional wireless issues connecting/reconnecting to my WiFi network. I usually take actions below when troubleshooting Mac OS X wireless problems.

Use airport utility to confirm proper signal strength and make sure the SSID and channel you are using for your network isn’t the same as your neighbors.

If you have Snow Leopard, use a free Snow Leopard wifi scanner to confirm proper signal strength and channel.

Once connected turn off the Airport status by holding “command” and “clicking mouse” and dragging icon to the desktop or by unchecking “Show airport status in menu bar” in Network Preferences. I believe this stops the background scans used by airport to track available networks and should make wireless more reliable [source].

Delete Mac OS X Preferred Networks

Delete all “Preferred Network” listings then re-enter into Network Preferences.

1. Open System Preferences and select the “Network” pane
2. Select “AirPort” and click “Configure”
3. In the “By default, join:” pull-down menu, select “Preferred networks”
4. Delete the network(s) you regularly use from the list
5. Launch the “Keychain Access” application located in Applications/Utilities.
6. Click on the “Kind” filter at the top, and look for “AirPort network password” entries. Delete them.
7. Restart, or log out then back in.
8. Repeat steps 1-3, this time re-adding your regularly used AirPort networks to the list.
9. Restart or log out then back in.

[source]

Resetting Mac OS X Wireless

If all else fails and you still are having issues connecting your wireless network, try resetting your wireless network preferences.

1. Network preferences are stored in the ‘System’ file space (/Library) and the ‘User’ file space (~/Library) in the following files:
   System files (network and wireless): /Library/Preferences/SystemConfiguration/com.apple.network.identification.plist
   /Library/Preferences/SystemConfiguration/com.apple.airport.preferences.plist
   System Files (General configurations) /Library/Preferences/SystemConfiguration/preferences.plist
   802.1x Profiles: ~/Library/Preferences/com.apple.eap.profiles.plist
2. To reset default network settings, remove (or make copy and remove) all of the above files. You need to be in command line/terminal mode, to do that: Launch ‘Terminal’: Finder -> Applications -> Utilities -> Terminal From the UNIX Shell, create a directory to store old preferences:
3. cd ~
mkdir saved-preferences
Then, move all network preferences files to this backup folder:
4. mv ~/Library/Preferences/com.apple.eap.profiles.plist ~/saved-preferences
cd /Library/Preferences/SystemConfiguration
5. sudo mv * ~/saved-preferences

The “sudo” command will prompt for admin password to proceed and a reboot should be performed. [source]

Filed under: How To Guides, WLAN Troubleshooting | no comments yet, your thoughts are welcome

WLAN Book On Twitter

WLAN Book is on Twitter!

Please follow us @wlanbook.

If you are also on Twitter, let us know your username in the comments below and we will follow you too if your tweets are technology focused.

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Mac OS X Wireless Signal Strength in Snow Leopard

The AirPort item in the menu bar now includes signal strength for all available wireless networks, so you can see which access point has the best signal before selecting it. Four signal bars appear in the AirPort status icon in the menu bar. The more bars that are black, the higher the signal quality. The bars do not indicate the connection rate, as this will vary according to your environment. [source]

While I like the simplicity of the four levels of signal strength above I sometimes need signal strength in dBm. dBm is a more granular way of describing the wireless signal strength.

dBm (sometimes dBmW) is an abbreviation for the power ratio in decibels (dB) of the measured power referenced to one milliwatt (mW). It is used in radio, microwave and fiber optic networks as a convenient measure of absolute power because of its capability to express both very large and very small values in a short form. Compare dBW, which is referenced to one watt (1000 mW). In the more granular information about the signal strength. [wikipedia]

Wireless Signal Strength Using the Snow Leopard Menu Bar

Clicking the option key and the signal strength menu icon will display detailed information about the currently connected wireless network.

PHY Mode – is the type of 802.11 WiFi network (802.11 a/b/g/n)
BSSID – is the MAC address of the access point
Channel – current 802.11 channel
Security – authentication and encryption type
RSSI – received signal strength indicator, aka the signal signal strength in dBm. The closer the number to 0 the stronger the signal.
Transmit Rate – the data rate of the current connection

Airport Signal Strength in dBm Using “About This Mac”

Wireless signal strength is also available using the About This Mac menu bar option and navigating to Network > Airport section.

RSSI Signal Strength Airport Command Line Utility

The airport utility is located at location below.

/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I

Will provide information about the current wireless connection.

$ airport -I
     agrCtlRSSI: -64
     agrExtRSSI: 0
    agrCtlNoise: -91
    agrExtNoise: 0
          state: running
        op mode: station
     lastTxRate: 48
        maxRate: 54
lastAssocStatus: 0
    802.11 auth: open
      link auth: wpa-psk
          BSSID: 0:b:55:6:6f:2f
           SSID: SSID
            MCS: -1
        channel: 1

Wireless Signal Strength Using Graphical Tools

WiFi Scanner is a free 802.11 wireless scanner and connection manager for Mac OS X 10.6 Snow Leopard or later. It leverages the the newest CoreWLAN API in Snow Leopard. This will detect access points and clients in ad-hoc mode if the SSID is being broadcasted. It can be used for wireless site surveys, wireless discovery, and to connect to wifi networks. The tool reports signal strength in dBm and shows access point BSSID/MAC addresses.

Filed under: WLAN Design, WLAN Site Survey, WLAN Tools | no comments yet, your thoughts are welcome

Rogue Access Point Detection Using iWIDS

iWIDS is an online wireless instrusion detection system (WIDS) that leverages the wireless scanning capabilities of a Windows XP/Vista/7 PC to discover rogue access points and determine if they are plugged into the wired network.

Rogue Router Access Points (AP)

The most common type of rogue access point is a consumer grade access point router. These devices usually cost less than $75 and can be purchased from almost any electronic store.

The ease in setting up these devices to provide wireless connectivity is also why they tend to be the most common rogue access point found in enterprise networks.

Detecting Rogue Router APs

Rogue router APs are part access point, part router, and part multi-port switch.

They can be connected to a wired network using the LAN (trusted) port or the WAN (untruested port). Between the LAN and WAN port NAT is enabled so that that the single IP provided by the ISP can be shared by multiple users connected wirelessly or via teh wired switch.

In almost every case, the last octect of the LAN, WAN, and wireless interface MAC addresses are adjacent to each other. This means that the MAC addresses are +/- a few values from each other.

Leveraging this common MAC address characteristic of router APs, a combination of wired and wireless analysis can be used by iWIDS rogue wireless access point scanner to correctly determine if the router access point is plugged into your wired network.

iWIDS In Action

Below are results of a scan on our test network that has multiple access points and one consumer grade router access point plugged into the wired network. Using a Windows 7 PC that is wirelessly connected to the network via we scanned to see if the application could correctly determine which device was the rogue router AP.

The application correctly detected the rogue access point router (MAC adddress ending in :43 with blue highlight) and the two other access points.

System Requirements and Usage

• Latest version of Java recommended (tested using version 1.6 update 16)
• Windows Vista or Windows 7 PC with wireless network card enabled (not fully compatible with Windows XP at this time). Ethernet card can be plugged in to wired network and/or wireless connected wirelessly to wired network to be scanned :-)
• Wired Ethernet interface or wireless interface should have an IP address (DHCP or static) that is valid for network being scanned
• Wireless interface can be disconnected from wireless network
• After loading, software will automatically search for all IP addresses on wired network and compare to discovered wireless devices
• Detection results will be displayed in “Wireless Devices On Subnet” window.
• Results can be emailed by configuring applet with SMTP information. Enter text that should be included in email before and after results in pretext and posttext areas.

Test drive iWIDS on your home or work network. Please share your results by leaving a comment.

Filed under: WLAN Security, WLAN Tools | no comments yet, your thoughts are welcome

Wireless Access Point Router Autopsy

The most common types of access points are called wireless routers or cable/DSL routers. A Linksys WRT 54G is shown below. The most common use for this type of router is sharing an Internet connection.

Wireless Access Point Router Outer Shell

The main external parts and ports of a wireless access point router are described below.

Reset Button – this button resets the configuration of the wireless router. In addition to any custom wireless settings the admin password and IP address of the device gets reset.

WAN Port – this port connects to the cable/DSL modem that is provided by the Internet service provider. Or connect to a corporate LAN port.

LAN Ports – these ports provide wired access to the network and Internet connection.

Antenna – these antennas amplify the signal from the 802.11 wireless radio that is inside the enclosure.

Wireless Router Autopsy

To better understand the various parts of a wireless router (LAN, WAN, wireless card), shown below are the internal electronics of a first generation Linksys WRT 54G cable/DSL router.

Wireless Access Point Router Network Architecture

Wireless access point routers are a combination of a wireless access point, multi-port network switch, and an IP router. The router portion is a three-port/interface router (eth0, eth1, eth2). The LAN switch ports and wireless access point are connected to two ports on the “router” and are bridged together (br0) as a single LAN segment. Network traffic is routed between br0 and the WAN port (eth1).

Newer Single Board Wireless Routers

Current wireless access point hardware has evolved into a single board design where the wireless card is integrated into the board.

Also, newer designs may have multiple wireless cards and additional ports like USB or printer ports.

Filed under: Gadgets, WLAN Design | no comments yet, your thoughts are welcome