Wireless Access

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

First check what server is reporting long response times. 

Is it reported on wired or wireless?

Best, Gorazd

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

Thanks for responding.  Since the sensor is reporting this "High DHCP Response times", I assume its on the wireless.  When you say check what server is reporting the long response times, you mean which DHCP server?  

First check what server is reporting long response times. 

Is it reported on wired or wireless?

Best, Gorazd

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

Hi Peter.

It can also be wired link. And yes I mean DHCP server. You will most probably see several DHCP servers in UXI. Go into analytics where you have details logged to see more info.

Best, Gorazd

Thanks for responding.  Since the sensor is reporting this "High DHCP Response times", I assume its on the wireless.  When you say check what server is reporting the long response times, you mean which DHCP server?  

First check what server is reporting long response times. 

Is it reported on wired or wireless?

Best, Gorazd

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

it also depends on the thresholds you set and the networks that you are testing (wired and wireless) 

you can get the pcap from the sensor.

You can refer to this troubleshooting guide

Hi Peter.

It can also be wired link. And yes I mean DHCP server. You will most probably see several DHCP servers in UXI. Go into analytics where you have details logged to see more info.

Best, Gorazd

Thanks for responding.  Since the sensor is reporting this "High DHCP Response times", I assume its on the wireless.  When you say check what server is reporting the long response times, you mean which DHCP server?  

First check what server is reporting long response times. 

Is it reported on wired or wireless?

Best, Gorazd

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

Are they all the same version of sensors. We found the new UXI 6E sensors reported DHCP time values 3x that of the UXI 5E sensors. I opened a tac case, they applied a fix.

We got the update from the backend team.

It looks like the initial DHCP discover frame was being dropped / not egressing the client radio, which was leading to consistent high DHCP response times. The UXI sensor uses DHCLIENT to manage it's DHCP requests and the default configuration open is an exponential 10s backoff when the initial request is not responded to, leading to an approx. 10s reported DHCP response time. Adjusting the timing settings of the device resulted in improved DHCP response time of the newer generation device which is a little more susceptible to issues when L3 infrastructure is shared between SSIDs, based on how it associates and negotiates a wireless connection. The fix was applied on 18 December 2024 to "serial number of sensor" and has now been applied globally. The sensors are operating as expected but newer generation sensors make use of a different chipset which, will have different behavior when associating. There is no action needed from the customer's side.

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

Does anyone know if there are any recent known issues with sensors running firmware versions UX-G6EC or UX-G6C that would cause them to report "No response from DHCP server"?

Are they all the same version of sensors. We found the new UXI 6E sensors reported DHCP time values 3x that of the UXI 5E sensors. I opened a tac case, they applied a fix.

We got the update from the backend team.

It looks like the initial DHCP discover frame was being dropped / not egressing the client radio, which was leading to consistent high DHCP response times. The UXI sensor uses DHCLIENT to manage it's DHCP requests and the default configuration open is an exponential 10s backoff when the initial request is not responded to, leading to an approx. 10s reported DHCP response time. Adjusting the timing settings of the device resulted in improved DHCP response time of the newer generation device which is a little more susceptible to issues when L3 infrastructure is shared between SSIDs, based on how it associates and negotiates a wireless connection. The fix was applied on 18 December 2024 to "serial number of sensor" and has now been applied globally. The sensors are operating as expected but newer generation sensors make use of a different chipset which, will have different behavior when associating. There is no action needed from the customer's side.

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

so are you saying that sensors are reporting incorrectly ?

Does anyone know if there are any recent known issues with sensors running firmware versions UX-G6EC or UX-G6C that would cause them to report "No response from DHCP server"?

Are they all the same version of sensors. We found the new UXI 6E sensors reported DHCP time values 3x that of the UXI 5E sensors. I opened a tac case, they applied a fix.

We got the update from the backend team.

It looks like the initial DHCP discover frame was being dropped / not egressing the client radio, which was leading to consistent high DHCP response times. The UXI sensor uses DHCLIENT to manage it's DHCP requests and the default configuration open is an exponential 10s backoff when the initial request is not responded to, leading to an approx. 10s reported DHCP response time. Adjusting the timing settings of the device resulted in improved DHCP response time of the newer generation device which is a little more susceptible to issues when L3 infrastructure is shared between SSIDs, based on how it associates and negotiates a wireless connection. The fix was applied on 18 December 2024 to "serial number of sensor" and has now been applied globally. The sensors are operating as expected but newer generation sensors make use of a different chipset which, will have different behavior when associating. There is no action needed from the customer's side.

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?

When I can't find any issues on the DHCP or DNS side that would explain the timeouts, I start to wonder if the sensors might be reporting false positives. I'm not 100% certain-just trying to look around and find the root cause of this issue.  

I've reviewed our DHCP and DNS configurations and haven't found anything that should be causing these timeouts. I also tested by connecting a sensor via an Ethernet cable on the same wireless VLAN, which bypasses the wireless gateways (in our case, the 9106). The sensor connected over Ethernet did not report any of these issues.

Once again, I'm not 100% certain-just trying to look around and find the root cause of this issue.

I have another thread open with a similar topic here

so are you saying that sensors are reporting incorrectly ?

Does anyone know if there are any recent known issues with sensors running firmware versions UX-G6EC or UX-G6C that would cause them to report "No response from DHCP server"?

Are they all the same version of sensors. We found the new UXI 6E sensors reported DHCP time values 3x that of the UXI 5E sensors. I opened a tac case, they applied a fix.

We got the update from the backend team.

It looks like the initial DHCP discover frame was being dropped / not egressing the client radio, which was leading to consistent high DHCP response times. The UXI sensor uses DHCLIENT to manage it's DHCP requests and the default configuration open is an exponential 10s backoff when the initial request is not responded to, leading to an approx. 10s reported DHCP response time. Adjusting the timing settings of the device resulted in improved DHCP response time of the newer generation device which is a little more susceptible to issues when L3 infrastructure is shared between SSIDs, based on how it associates and negotiates a wireless connection. The fix was applied on 18 December 2024 to "serial number of sensor" and has now been applied globally. The sensors are operating as expected but newer generation sensors make use of a different chipset which, will have different behavior when associating. There is no action needed from the customer's side.

I have 3 sensors, one per floor.  One of the sensors is showing "High DHCP Response times".  1 - Why is only one of the sensors reporting this issue?  2 - How do you start to troubleshoot?