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mhatrak
0 pts.
 wireless networks
Wireless
HAs anyone ever had a wireless network that they could see the access points but could not connect to them.
ASKED: Mar 23, 2006  3:10 PM GMT
UPDATED: March 26, 2006  7:24:58 AM GMT
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BobYoung
0 pts.
Answer Wiki:
mhatrack,

There are several reasons why you might be able to see a wireless network but not be able to connect to it.
1) The Access Point (AP) is using MAC filtering, and your MAC address is not in the permission table.
2) The AP is set to allow a certain number of connections (for example, it allows 5 users to connect at any one time), and all connections are in use. This is usually adjusted by controlling the number of IP addresses the AP can assign with DHCP.
3) The AP is configured as the gateway to a VPN port, and your laptop isn't configured with the right credentials.
4) Signal strength may be inadequate to sustain a connection.
5) The AP may need to be rebooted.
6) The laptop or its wireless card may need to be rebooted.
7) The network behind the AP is currently turned off. If the AP is connected to power, you'll still see the AP, even though you can't connect to the network behind it.

You didn't mention encryption or authentication, so I'm assuming you're asking about an "open" system. Naturally, it will be difficult to connect if the AP is using WEP or WPA encryption, or is connected to an authentication server, unless you're an authorized user. I listed the VPN scenario (item 3 above) separately from this paragraph about encryption and authentication because the AP can truly be "wide open" - no special configuration at all - if its only TCP/IP connection is to a VPN. Unless you're authorized, you won't be able to connect, but you'll see the AP just fine.
--Bob Young
Last Wiki Answer Submitted:  Mar 23, 2006  5:34 PM (GMT)  by  BobYoung   0 pts.
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Thank you for a reply. What i am running is a Netgear Router that is connected directly to the cable modem. Then a switch is connected to the router which then the netgear access points are connected to the switch. I actually am in a school and have 2 classrooms that connect great and 1 that can not even get a good signal. I wasn’t sure if there was a virus out there that might cause this type of a problem. Any insight would be great

mhatrak
 0 pts.
 

mhatrak,

If you don’t have a good signal, then of course that will cause problems trying to connect. A virus isn’t likely to affect signal strength, unless it’s a very targeted virus and you’re using an AP with adjustable power settings.

I would suggest swapping APs between one of the good classrooms and the bad classroom. If the signal strength map is still the same, then the APs are okay and you have a coverage issue. If the signal strength map changes (for example, if the low signal moves with the AP from the bad classroom), then you have a bad AP.

–Bob Young

BobYoung
 0 pts.
 

If you are sure that the access point in the 2nd classroom is getting the IP address and the signal you are detecting in the 2nd classroom is from the same AP (not from the AP in room besides) then do the following. To make sure that the signals are from the same AP either check its MAC address or change the SSID in it (different from one being used in 1st classroom AP).

1. Increase the transmit power

But what i personally suspect is that AP in 2nd classroom is not functioning at all. One possible reason is the length of cable between AP and switch. To eliminate this possibility connect the 2nd AP to switch with the smaller utp cable. This happned to us once (cz the switch was of some inferior quality).

khawar
 0 pts.