Saturday, 9 July 2016

Hand carving your own wireless configurations

After Debian 6 "squeeze" network manager does not handle interfaces that  are in /etc/network/interfaces by default. You update the network manager configuration to inform it to handle those interfaces. Network Manager is included in many Linux distros. Its reason for living is to make Linux networking just work.

Network Manager will infinitely display a loading logo sign in Gnome if it does not handle the wireless interface.

There is no fun network manager handling all the juicy configuration.


What is involved when making your own wireless configurations:
  • Scanning all the wireless networks on the command line using iw
  • Looking at the details of wireless access point I want to connect to. I need to know if the authentication process it uses such as if its PSK (Pre shared key) or EAP (Extensible Authentician Protocol). I also need to know if there is a cipher required on top of the protocol.
  •  Once you have the information you can then add it to the wpa_supplicant.
 wpa_supplicant is just for the WPA protocol. For the WEP (Wired Equivalant Protocol) you use another application.  Reason is that nobody wants to touch the WEP application again. No one is using it because of the way you can sniff the packets and figure out the pre shared key being used which makes WEP unsecured.

Network Manager code

https://wiki.gnome.org/Projects/NetworkManager/Hacking

You can browse the code to see how it decides what information it needs for every network configuration.

What are the cipher used for?

TKIP and CCMP are used to encrypt your data from the computer to access point. They make sure no see what you are browsing. They use the pre shared key to encrypt the data to the router.



Here is an example of wireless printout from iwlist. It is a WPA2 router.
      Cell 06 - Address: 5C:DC:96:56:4F:F3  
           Channel:11  
           Frequency:2.462 GHz (Channel 11)  
           Quality=54/70 Signal level=-56 dBm   
           Encryption key:on  
           ESSID:"SSID"  
           Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 18 Mb/s  
                24 Mb/s; 36 Mb/s; 54 Mb/s  
           Bit Rates:6 Mb/s; 9 Mb/s; 12 Mb/s; 48 Mb/s  
           Mode:Master  
           Extra:tsf=0000000b307e393e  
           Extra: Last beacon: 28ms ago  
           IE: Unknown: 000B4254487562352D4A354A37  
           IE: Unknown: 010882848B962430486C  
           IE: Unknown: 03010B  
           IE: Unknown: 0706474220010D14  
           IE: Unknown: 2A0106  
           IE: Unknown: 2F0106  
           IE: IEEE 802.11i/WPA2 Version 1  
             Group Cipher : CCMP  
             Pairwise Ciphers (1) : CCMP  
             Authentication Suites (1) : PSK  

 Information you need from this print out
  • ESSID
  • Group Cipher
  • Pairwise Cipher
  • Authentication Suites
You can then add this to /etc/wpa_supplicant/wpa_supplicant.conf
 network={  
     ssid="SSID"  
     key_mgmt=WPA-PSK  
     pairwise=CCMP   
     group=CCMP  
     psk=<your psk passphrase produced by wpa_passphrase>  
     priority=1  
 }  


That is a general over view to make your own wireless configurations.

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