topic Re: A couple of more questions: in Network Access Control

Unable to collect dhcp information using device-sensor for profiling.

twan.wing — Mon, 11 Mar 2019 06:56:15 GMT

I am trying to do dot1x/MAB authentication (there is no issue here), but I want to collect dhcp information of the devices asking for IP address from dhcp-server for profiling using device-sensor (cdp is being collected - no issue) but when I check for dhcp # show device-sensor cache all, there is no single entry for dhcp data.

The dhcp server is on the switch where these devices are trying to access the network from and this should be the case. However, I noticed the following which I do not know if it is related (from #debug device-sensor error) - same error appear with different X value.

DSensor: NULL input physical interface, discarding packetRejecting packet on SVI Interface VlanX

I am more concerned about collecting the attributes now rather than sending them..!

Switch IOS: Version 15.0(2)SE9

any suggestions?

Hi there, I have a couple of

nspasov — Mon, 18 Jul 2016 23:18:15 GMT

Hi there, I have a couple of questions:

1. Are any of the devices using static IPs?

2. What model switch are you using?

3. Can you post the output of your device-sensor configs?

4. Do you have the RADIUS probe enabled in ISE?

Thank you for rating helpful posts!

Hi Neno,

twan.wing — Tue, 19 Jul 2016 01:37:09 GMT

Hi Neno,

1. none of them is using static IP.

2. 3750-x

device-sensor accounting

device-sensor notify all-changes

device-sensor filter-list dhcp list Users_att
option name host-name
option name requested-address
option name parameter-request-list
option name class-identifier
option name client-identifier
option name user-class-id
device-sensor filter-spec dhcp include list Users_att

aaa accounting dot1x default group radius

radius-server vsa send accounting

access-session template monitor

4. Yes, Radius and DHCP probes are enabled,

A couple of more questions:

nspasov — Tue, 19 Jul 2016 04:22:34 GMT

A couple of more questions:

1. Do you have dhcp snooping enabled?

2. Do you see bindings in the dhcp snooping database?

Thank you for rating helpful posts!

Thank you veery veery much.

twan.wing — Tue, 19 Jul 2016 23:04:05 GMT

Thank you veery veery much. now Devic-Sensor is collecting the data after enabling dhcp-snooping globally and on the the vlans which the users are connected to.

Dhcp-snooping was not enabled for me, but after enabling device-sensor cache shows dhcp data. Thanks again 🙂

You are welcome! Glad I was

nspasov — Wed, 20 Jul 2016 16:08:37 GMT

You are welcome! Glad I was able to help! 🙂

DHCP Snooping enabled

bledi_vako — Thu, 09 May 2019 10:59:53 GMT

I have a very similar issue, and I do have DHCP Snooping enabled as well.

But the DHCP information is not showing in the output of "show device-sensor cache", and ISE is not profiling neither Cisco IP phones.

Re: A couple of more questions:

MSJ1 — Mon, 02 Feb 2026 18:54:43 GMT

Hello @nspasov

After I enabled dhcp snoping for vlans on switch , ISE started profiling correctly the endpoints. Before I enabled dhcp snooping on vlans from that switch device-sensor was showing only cdp data but now after I enabled dhcp snooping I can see device-sensor is showing dhcp data as well.

If you can give a little bit more clue on whats the relation of dhcp snooping with device-sensor that it ( device-sensor ) was not showing dhcp data before I enable dhcp snooping ?

Re: Unable to collect dhcp information using device-sensor for profili

PSM — Tue, 03 Feb 2026 07:57:43 GMT

@MSJ1 Device Sensor is dependent on DHCP snooping for the DHCP data. Just like it is dependent on CDP and LLDP to be enabled for it to collect CDP and LLDP attributes.