How to use Packet Capture utility to trace DNS packets.

MVP Expert
MVP Expert

This article describes how to use packet capture utility to capture and display DNS packets, sent and received from the Mobility Controller.


In the following example, the Mobility Controller is configured for DNS domain lookup. The CLI “packet-capture controlpath” command, captures packet destined for the managed device for protocols TCP and UDP with port 53.


********** DNS configuration/verification **********


(Mobility-Controller) *[mynode] (config) #ip domain lookup
(Mobility-Controller) *[mynode] (config) #ip domain-name
(Mobility-Controller) *[mynode] (config) #ip name-server
(Mobility-Controller) *[mynode] (config) #ip name-server


(Mobility-Controller) *[mynode] #show ip domain-name
IP domain lookup:       Enabled
IPv6 domain lookup:     Enabled
IP Host.Domain name:

DNS servers
=========== *


********** DNS packets destined for the managed device **********


(Mobility-Controller) *[mynode] #packet-capture controlpath tcp 53
(Mobility-Controller) *[mynode] #packet-capture controlpath udp 53


(Mobility-Controller) *[mynode] #show packet-capture

Active Capture Destination
Destination    Disabled

Active Capture (Controlpath)
Interprocess   Disabled
Sysmsg         Disabled
TCP            Enabled    Ports: 53
UDP            Enabled    Ports: 53
Other          Disabled


A DNS client ( made a query for the name This query was sent to the name server ( and the response was forwarded to the DNS client.


(Mobility-Controller) *[mynode] #show packet-capture controlpath-pcap

14:48:02.704422 IP > 21+ A? (43)
14:48:02.704620 IP > 13618+ A? (43)
14:48:02.757313 IP > 13618 1/0/0 A (59)
14:48:02.757431 IP > 21 1/0/0 A (59)
Version history
Revision #:
2 of 2
Last update:
‎02-06-2019 04:04 PM
Updated by:
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