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Cisco Bug: CSCus80423 - CISCO1921/K9 / DNS process caused cpu hog and router crash

Last Modified

Aug 24, 2017

Products (74)

  • Cisco IOS
  • Cisco 888W Integrated Services Router
  • Cisco 892W Integrated Services Router
  • Cisco VG204XM Analog Voice Gateway
  • Cisco 812 CiFi Integrated Services Router
  • Cisco 881SRSTW Integrated Services Router
  • Cisco 861W Integrated Services Router
  • Cisco C897VA Integrated Services Router
  • Cisco 819 Hardened Integrated Services Router
  • Cisco C892FSP Integrated Services Router
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Known Affected Releases

15.3(3)M

Description (partial)

<B>Symptom:</B>
HIGH cpu observed due to DNS process and all the following DNS request are dropped .

<B>Conditions:</B>
If a device is configued to support DNS requests, when under a DNS flood attack the DNS service may fail to respond and the CPU on the device 
will increase.  In occassions the device will reset and reload.

Will see message such as:
%SYS-3-CPUHOG: Task is running for (72004)msecs, more than (2000)msecs (48/13),process = DNS Server.
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Bug Details Include

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  • Status
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