Router ruins wireless network by jamming two Cisco WAP 371 access points
Dear Experts
I am not able to get a wireless network to function. Please help me understand what is going on.
I have the following hardware:
Two Cisco WAP 371 accesspoints
Cisco Small Business SG200-10FP switch with PoE
Small unmanaged DLink 4 port switch
Router from ISP. Brand not known. The internet connection is fiber and has 50Mbits up and down.
Network diagram:
Router -> Cisco Switch -> 2x Access Points
Laptops and iPhones can connect to the wireless network but speedtest failes on all devices. Sometimes it gets 0.2Mbits up and down.
If I connect to the switch using a wire then internet connection is perfect - 50Mbits both ways.
I tried to change the passwords for both SSID's (2.4 and 5 Ghz) without luck. Changed the access points login password. These two steps were made to exclude any potential hack or unwanted usage of the wireless network. No luck.
The wireless and ethernet led indicators blinks continuously.
I have take the access point to a different location and there they work perfectly. No configuration change compared to the problematic site. The laptops and iPhones works perfectly in other wireless networks.
I was thinking of noise and the I borrowed a radio frequency analyser and examined the 2.4 and 5Ghz areas. If the access points are turned off there is no signal so I excluded the possibility of noise. But when I turned on the access points there is continuous signal in the 2.4 and 5Ghz areas. I have attached an image of the 2.4 Ghz area. Normally access points only transmit when data is being transmitted. I checked my own wireless network and confirmed this.
If I disconnect the router then the RF signal disappears and the LED indicators stop blinking. If I connect the router again the RF goes up again and the LEDs start blinking.
When doing a local share on one laptop and downloading a large file from laptop 1 to laptop 2 and no router is connected then a get a transmit speed of 6-8 megabyte per second. If I connect the router then no download is possible from laptop 1 to laptop 2.
So I only conclude that the router must do something bad. I have ordered a new one.
But how can a router do this? Is there a mechanism where a router can jam a wireless network?
I am hoping that the new router fixes the problem, but I am still rather concerned.
Thank you in advance for your time and expertise.
Atb Anker
IMG-1662.JPG
I am not able to get a wireless network to function. Please help me understand what is going on.
I have the following hardware:
Two Cisco WAP 371 accesspoints
Cisco Small Business SG200-10FP switch with PoE
Small unmanaged DLink 4 port switch
Router from ISP. Brand not known. The internet connection is fiber and has 50Mbits up and down.
Network diagram:
Router -> Cisco Switch -> 2x Access Points
Laptops and iPhones can connect to the wireless network but speedtest failes on all devices. Sometimes it gets 0.2Mbits up and down.
If I connect to the switch using a wire then internet connection is perfect - 50Mbits both ways.
I tried to change the passwords for both SSID's (2.4 and 5 Ghz) without luck. Changed the access points login password. These two steps were made to exclude any potential hack or unwanted usage of the wireless network. No luck.
The wireless and ethernet led indicators blinks continuously.
I have take the access point to a different location and there they work perfectly. No configuration change compared to the problematic site. The laptops and iPhones works perfectly in other wireless networks.
I was thinking of noise and the I borrowed a radio frequency analyser and examined the 2.4 and 5Ghz areas. If the access points are turned off there is no signal so I excluded the possibility of noise. But when I turned on the access points there is continuous signal in the 2.4 and 5Ghz areas. I have attached an image of the 2.4 Ghz area. Normally access points only transmit when data is being transmitted. I checked my own wireless network and confirmed this.
If I disconnect the router then the RF signal disappears and the LED indicators stop blinking. If I connect the router again the RF goes up again and the LEDs start blinking.
When doing a local share on one laptop and downloading a large file from laptop 1 to laptop 2 and no router is connected then a get a transmit speed of 6-8 megabyte per second. If I connect the router then no download is possible from laptop 1 to laptop 2.
So I only conclude that the router must do something bad. I have ordered a new one.
But how can a router do this? Is there a mechanism where a router can jam a wireless network?
I am hoping that the new router fixes the problem, but I am still rather concerned.
Thank you in advance for your time and expertise.
Atb Anker
IMG-1662.JPG
SOLUTION
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I'd parse this problem as either a networking problem - as distinct from an actual wireless/rf problem
or a wireless/rf problem.
You didn't say if the WAPs are getting their IP addresses from the router DHCP. Are they?
The WAPs have extensive information in Status and Statistics. What differences do you see when the router is connected / not connected?
Presumably WDS is turned off, correct?
WorkGroup Bridge mode is turned off, correct?
QoS is turned off, correct?
The WAPs are not set up as secure wired network supplicants, correct?
I have to wonder if there's an IP address conflict or a subnet mask mismatch.
From a wireless/rf point of view:
What do you see if you use something like inSSIDer on a laptop? With and without the router involved?
I don't understand the comment that an Access Point will only transmit when there's a data transfer. After all, the thing has to do handshaking, etc. and needs to be up all the time. How would the first laptop connect otherwise, etc. etc.
So, there may be some misunderstanding here that would be good to clear up.
or a wireless/rf problem.
You didn't say if the WAPs are getting their IP addresses from the router DHCP. Are they?
The WAPs have extensive information in Status and Statistics. What differences do you see when the router is connected / not connected?
Presumably WDS is turned off, correct?
WorkGroup Bridge mode is turned off, correct?
QoS is turned off, correct?
The WAPs are not set up as secure wired network supplicants, correct?
I have to wonder if there's an IP address conflict or a subnet mask mismatch.
From a wireless/rf point of view:
What do you see if you use something like inSSIDer on a laptop? With and without the router involved?
I don't understand the comment that an Access Point will only transmit when there's a data transfer. After all, the thing has to do handshaking, etc. and needs to be up all the time. How would the first laptop connect otherwise, etc. etc.
So, there may be some misunderstanding here that would be good to clear up.
ASKER
WAPS have static IP.
Not examined: The WAPs have extensive information in Status and Statistics. What differences do you see when the router is connected / not connected?
Yes: Presumably WDS is turned off, correct?
Yes: WorkGroup Bridge mode is turned off, correct?
Yes: QoS is turned off, correct?
Yes: The WAPs are not set up as secure wired network supplicants, correct?
If this was the problem I would it very to explain the problem: I have to wonder if there's an IP address conflict or a subnet mask mismatch.
From an RF point of view then yes there is handshaking, SSID broadcast and that kind of RF transmission, but if I use the exact same settings on my on my FieldFox to analyze RF then handshaking etc. would not explain the broad RF amplitude i.e sending massive RF continuously over the entire channel. I confirmed this a two other locations with wifi.
I have not tried inSSID, but I will try that as soon as om in site again.
Thanks
Not examined: The WAPs have extensive information in Status and Statistics. What differences do you see when the router is connected / not connected?
Yes: Presumably WDS is turned off, correct?
Yes: WorkGroup Bridge mode is turned off, correct?
Yes: QoS is turned off, correct?
Yes: The WAPs are not set up as secure wired network supplicants, correct?
If this was the problem I would it very to explain the problem: I have to wonder if there's an IP address conflict or a subnet mask mismatch.
From an RF point of view then yes there is handshaking, SSID broadcast and that kind of RF transmission, but if I use the exact same settings on my on my FieldFox to analyze RF then handshaking etc. would not explain the broad RF amplitude i.e sending massive RF continuously over the entire channel. I confirmed this a two other locations with wifi.
I have not tried inSSID, but I will try that as soon as om in site again.
Thanks
Yes. My concern here is that having a FieldFox may give different kinds of information (e.g. the integration time may be different) so you see things that one can't see with inSSIDer. And, that difference in information could be confusing. So a comparison with something that lots of folks are familiar with might be a very good idea. That said, there's no doubt that a FieldFox would be in many ways a better instrument.
I would be very tempted to set the WAPs for DHCP and see what happens. You can always revert to static IPs later.
I would be very tempted to set the WAPs for DHCP and see what happens. You can always revert to static IPs later.
I agree with Fred; it's a TCP/IP issue rather than a wireless issue. Take it back to basics. Configure your clients to use DHCP and test with the router on. What happens?
ASKER
But why are are the two access points working perfectly when the APs are placed at a different location? I made no change in the APs configuration when testing the access points at the other location.
The IP address range is the same at both lo ations: 192.168.1.x / Subnet: 255.255.255.0 / Router: 192.168.1.1
Nothing fancy.
The IP address range is the same at both lo ations: 192.168.1.x / Subnet: 255.255.255.0 / Router: 192.168.1.1
Nothing fancy.
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ASKER
Hi Fred and craigbeck
Thank you very much for your responses.
I have finally been able to be onsite and examine the problem further. A friend of mine advised me to do a wireshark sniffing session and that hit the nail.
The problem was a multicast/broadcast TV signal in form of UDP packets. As soon a the router detected the TV box then the router startet the broadcast on all port on the switch. This explains why the wireless accesspoint where transmitting all the time.
The simple solution was to keep TV box in its own port of the router and the switch with accesspoint in a another port on the router.
In retrospect I did not inform about the entire network and I will remember this to next time.
Thank you again for your time.
atb Anker
Thank you very much for your responses.
I have finally been able to be onsite and examine the problem further. A friend of mine advised me to do a wireshark sniffing session and that hit the nail.
The problem was a multicast/broadcast TV signal in form of UDP packets. As soon a the router detected the TV box then the router startet the broadcast on all port on the switch. This explains why the wireless accesspoint where transmitting all the time.
The simple solution was to keep TV box in its own port of the router and the switch with accesspoint in a another port on the router.
In retrospect I did not inform about the entire network and I will remember this to next time.
Thank you again for your time.
atb Anker
ASKER
The transmit rate between laptop 1 and laptop 2 is 6-8megabytre per second if the router is off.
If the router is on the nothing can be transmitted between the two laptops.