puzzling wireless security problem

funkyCable · 21-12-2005, 09:47

I am set up a wireless network for a friend who is on AOL. I did not use windows version of wireless security on my friends laptop (at least not that i am a ware of).

Friends Laptop
XP sp2
Belkin Usb adaptor

Router (Thompson speedtouch 576)

I am using the router to setup security and have enable WPA (TIK) settings and inputted into on to the laptop using the software that come with the belkin. Everything worked fine until exactly 1 week later it could not connect but when i disable the security it works.

Does it change the key after a week or is there a setting which i am missing.

any help much appreciated.

**Chris** · 21-12-2005, 10:05

Quote:

Originally Posted by funkyCable

I am set up a wireless network for a friend who is on AOL. I did not use windows version of wireless security on my friends laptop (at least not that i am a ware of).

Friends Laptop
XP sp2
Belkin Usb adaptor

Router (Thompson speedtouch 576)

I am using the router to setup security and have enable WPA (TIK) settings and inputted into on to the laptop using the software that come with the belkin. Everything worked fine until exactly 1 week later it could not connect but when i disable the security it works.

Does it change the key after a week or is there a setting which i am missing.

any help much appreciated.

Ensure that you are using WPA with Pre Shared Key (PSK). WPA does change the encryption periodically, I guess if you have not set this up on the laptop it could lose the connection. Not sure if that is the problem but definitely worth checking. Open your Belkin utility and ensure it is configured for WPA-PSK. TKIP should also be there somewhere but it sounds like you did that already.

funkyCable · 21-12-2005, 10:25

what exactly is tkip? after reading the manual it sounds as if it is a temporary key which is used. I have selected this option and keyed in the key on the laptop.

Here is the manual.

Stuart · 21-12-2005, 10:26

Also bear in mind that if the signal is weak (or Windows rates it anything lower than "Good"), then Windows is more likely to have trouble maintaining a secure connection than it will an insecure one.

Try (if possible) moving the router.

---------- Post added at 10:26 ---------- Previous post was at 10:25 ----------

Quote:

Originally Posted by funkyCable

what exactly is tkip? after reading the manual it sounds as if it is a temporary key which is used. I have selected this option and keyed in the key on the laptop.

Here is the manual.

TKIP is a form of encryption. Not sure if it's part of the WPA standard, but most routers (and Windows) offer a choice between AES and TKIP encryption. Not sure which is best, but I normally use TKIP.

**Chris** · 21-12-2005, 10:41

You can use TKIP with WPA. I do.

funkyCable · 21-12-2005, 10:42

when you say normally are you using windows do to the key?

Aragorn · 21-12-2005, 10:46

An overview of WPA can be found here, including

Quote:

Temporal Key Integrity Protocol (TKIP)

For 802.11, Wired Equivalent Privacy (WEP) encryption is optional. For WPA, encryption using TKIP is required. TKIP replaces WEP with a new encryption algorithm that is stronger than the WEP algorithm but that uses the calculation facilities present on existing wireless devices to perform encryption operations. TKIP also provides for the following: •The verification of the security configuration after the encryption keys are determined.• The synchronized changing of the unicast encryption key for each frame.• The determination of a unique starting unicast encryption key for each preshared key authentication.

As I understand it, the 'Pre-Shared Key' (PSK) is used as the basis for generating session keys for TKIP. So while the PSK should not change (and should be identical on router and all clients) the session keys will change dynamically.

All you should need to worry about is -
All devices are set identically, eg WPA-PSK with TKIP
All devices have the same PSK.

funkyCable · 21-12-2005, 10:48

I know you can use TKIP with WPA as it askes you which one you want to use as soon as you choose wpa

Stuart · 21-12-2005, 11:01

Quote:

Originally Posted by funkyCable

when you say normally are you using windows do to the key?

I personally do use Windows to Manage the connection. I have a Belkin Wireless PC card and the software I got with that, while it does provide all sorts of statistics and features, it isn't that good at maintaining the connection. There is an option somewhere there to allow Windows to manage the connection.