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Wireless access points constantly dropping connections

Posted on 2010-09-20
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Last Modified: 2013-12-21
In our high school building we have 8 Linksys WAP54g access points. They all have the same SSID and the channels are different because they are somewhat close to each other. I had recently gone around and reset to factory defaults / setup from scratch because of this issue.

Staff are complaining that they get kicked off the wireless. They have to re-connect to the wireless and sometimes are unable to do so. This happens daily, sometimes happens every other day. This issue started at the beginning of this school year. The WAPs were most likely left on all summer. We have migrated to Windows 2008 R2 from Novell, and have a new DNS server.

The power in the building is very poor, do you think they could have been surged over the summer?

We did not have this issue prior to this school year. We just placed all of these access points last November. I don't know what else to do to stop the access points from kicking staff off. They all have Acer TravelMate 5730 laptops.
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Question by:danisham
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23 Comments
 
LVL 32

Expert Comment

by:willcomp
ID: 33719381
Start with DHCP settings (lease time) on the server. Server changed access points did not. Always start troubleshooting with what changed.
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Author Comment

by:danisham
ID: 33719447
I know that we increased the lease time to be the length of the school year since it would be easier to administer the computers via VNC, and other for other reasons. Could you explain the possible correlation between lease times given out by DHCP and dropped connections while connected wirelessly? Do I need to make adjustments on the WAP itself?
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LVL 32

Expert Comment

by:willcomp
ID: 33720222
If DHCP works properly, it should renew well before address expires. That was just a starting place.

My main point is to start with what changed rather than the access points. With that many access points, the problem is likely either server or router related.

Connect a notebook using wireless and static IP address. Connect a PC to router using an ethernet cable. See if either one drops connection.
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LVL 20

Expert Comment

by:Iain MacMillan
ID: 33723316
if you reset the access points, check if they require a firmware upgrade for improved range/ability, also most AP's enable DHCP themselves by default, unless disabled, so you may find the issue is the users/staff are trying to get an IP from an AP and not the DHCP server that they are supposed to.

disable DHCP on all AP's and then make sure they all get static or reserved IP's from the DHCP server, less admin work or headaches.  check DNS, Gateway and DHCP are all working correctly.  You should be able to save a config/backup file with all these settings, and then upload to each device and make the subtle changes required.
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Author Comment

by:danisham
ID: 33724166
We have set the APs to be an access point with static IPs. There isn't a place I can specify the DNS server in the AP. The firmware is showing ver. 3.04 which I assumed was up to date.
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Author Comment

by:danisham
ID: 33725784
I am currently using WPA2 - Mixed mode, I read somewhere that when users are roaming between multiple WAPs that the WAP should be set to WPA2 - TKIP. Can I get any feedback on that?
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LVL 20

Expert Comment

by:Iain MacMillan
ID: 33725904
not sure on that, you could test it with 2 devices.  if you can connect to them remotely ok, you power supply should be fine, or do you power them over the Ethernet link (POE) from the switch?

i would try and use a WPA & WPA2 combo, as some older devices may not support WPA2, most AP's offer the choice of both.
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Author Comment

by:danisham
ID: 33725926
They aren't POE. I was just seeing if there was a big performace difference with WPA2- Mixed versus WPA2 - Personal. Sorry for not clarifying that in previous post. WPA2 - Mixed is both TKIP + AES, WPA2 - Personal is just AES, at least that is what the WAP54G interface is stating.
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Expert Comment

by:Iain MacMillan
ID: 33726086
yes but you need to cater for all Wi-Fi devices, and unless you know they all support WPA2 specifically, you will have lots of folk not being able to connect if their device only supports WPA.

I use WPA1 & 2 Personal on my Wi-Fi AP devices, as I also have to cater for different Blackberry handsets, and older laptops.
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Author Comment

by:danisham
ID: 33726311
I am going to check server settings and make sure all WAPs have current firmware. I will update you guys with my progress, as it seems this might take some trial and error.
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LVL 32

Expert Comment

by:willcomp
ID: 33726599
When clients (laptops) lose connection, does it affect all laptops at about the same time or is it random?
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Author Comment

by:danisham
ID: 33726758
I am almost positive it is random, I will double check with the building tech. One teacher told me when he power cycles the WAP the staff are able to connect. There are two WAPs very close to each other. They are on different channels but there is no need for 2 to be that close so I am going to remove one of them to see if that helps that wing of the building.
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Author Comment

by:danisham
ID: 33728930
Well something tells me Willcomp is correct here. We have problems actually with all WAPs across the district with mapped drives not showing up and authentication issues. We have a mobile cart with a WAP54G and it has been reported that they can't access their personal drives / they are not showing up. I also had problems joining certain computers to the domain wirelessly. Anybody have similar wireless authentication issues similar to my issue? Perhaps that has to deal with the staff losing connection randomly on their laptops. We had a third party company setup our DHCP / DNS servers since we did migrate to Server 2008 R2.
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LVL 32

Expert Comment

by:willcomp
ID: 33729013
I can't help you with specifics on Server 2008 (my experience ended with 2000 Server and I'm way past cold on server OSes) but I'm sure there is someone here who can. If need be, click on Request Attention button and ask a moderator to send out a call for help.

What about the contractor who installed the servers and network? Can you get them to fix the problem?
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LVL 20

Accepted Solution

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Iain MacMillan earned 500 total points
ID: 33732312
it seems that the AP's are not connected to the domain correctly, that they are not talking to the DC, which is needed to authenticate everyone trying to access them.  can you also test by removing the encryption on one node for testing, for the reasons i gave above -- try it out in the most simplest terms, no encryption and set to channel 6 or 11, and test with a laptop right next to the AP.

  1. check the Linksys site for firmware updates, just incase something is required for a 2008 domain structure (pity you don't have a 2003 DC as well).  
  2. check your DC to make sure it sees the devices, and that they have a IP within the range of your DHCP scope and also show on the DNS manager.  
  3. verify that you have the latest Acer wi-fi drivers for your laptop's OS.
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Author Comment

by:danisham
ID: 33733415
lainNIX: I will try your suggestions this afternoon and keep you posted. The encryption hasn't changed from last year, but I will definetly try that.
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Author Comment

by:danisham
ID: 33734609
Well the DHCP server here at the board office is currently being plugged into an unmanaged Allied Tellysn switch. That switch is running to a drop on the wall, then that drop is being punched to a switch to go the DC in the elementary school. Is there a limit to how many hops there can be? Perhaps I need to run the server straight to a drop in the wall. I am a younger tech and the operations part of my job is new this is all a learning experience for me.
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LVL 20

Expert Comment

by:Iain MacMillan
ID: 33734614
ok cool, if you reset them, the encryption setting & keys would also reset.
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LVL 20

Expert Comment

by:Iain MacMillan
ID: 33734944
ok do you have a separate DHCP service on the DC at the school, as well as the board office, but you usually only have one DHCP server, you can do an overlap/split like 60/40 with the whole IP range, as a fail-over incase your main DHCP server fails, but really there is normally just one controlling the issuing of addresses.

for servers I would always recommend managed switches, so you can set and control port speed and duplex settings, and team up dual NICs that most servers have, to be one big dual connection -- thus boosting the ability and speed of the server to pass data around the network.  Servers normally get static IP addresses, and ports normally fixed at 100MB FULL or 1000MB FULL if you have Gigabit.  Switches are normally interlinked by either a crossed CAT5e or 6 cable, or a GBIC fibre cable depending on your switch hardware.  If you are having other technical issues other than the AP one, then it maybe network related, but ask your comms guy to double check.  For small numbers of servers, it may help to have them connect to the same switch, your wall-ports will patch back to the main comms room, and usually from, there into a switch port.
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Author Comment

by:danisham
ID: 33735388
lainNIX: Thank you for your advice. We have one DHCP server, and 3 DCs all replicating AD to eachother. We have our contractor who initially setup our servers looking into the DHCP scope and lease times. She was currently checking Kerberos errors in Event Viewer. I will keep you posted.
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Expert Comment

by:Iain MacMillan
ID: 33790291
did you get it all sorted in the end???
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Author Comment

by:danisham
ID: 33790419
The person who setup the DNS and DHCP servers made some changes, and we eliminated the one switch the DNS / DHCP server was running into, so one less hop going out across the network. I am going to speak with our contractor about what has been done but I know it had something to do with authentication and wireless not authenticating / initializing before someone was fully logged into the machine. We are hiring a contractor to do a professional site survey which should help the signals at least. People aren't loosing connection but the signal availability is still an issue. We want to get a WLAN controller and not have to resort to cheap WAP54G APs in a professional school environment.
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LVL 20

Expert Comment

by:Iain MacMillan
ID: 33796437
ok good luck.  might i suggest looking at something like Cisco Aironet.

http://www.cisco.com/en/US/prod/wireless/wireless_for_enterprise.html
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