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Home > Success Center > Archive > 2017November15 - Cleanup > Authentication failure in traps in SolarWinds NPM

Authentication failure in traps in SolarWinds NPM

Updated: October 26, 2017


Some devices send Traps with the following message:

"SNMPv2-MIB:authenticationFailure" and value cExtSnmpTargetAuthInetAddr=



  • NPM


Possible causes to trigger "authenticationFailure trap" include:

  • Vlan Polling - Note: trap frequency should correspond to topology polling Interval, Default Node Topology Poll Interval, default is 30 Min
  • NCM jobs running

Another possibility of Error "SNMPv2-MIB:authenticationFailure"  is NCM Jobs running. Verify that Traps are received at the same time NCM jobs are running.

For more information about authenticationFailure traps, see  (© 2017 Cisco, available at, obtained on November 10, 2017)


Disable Vlan polling on the affected device.

See Receive trap in NPM with an extra IP for more information. 

cExtSnmpTargetAuthInetAddr = 


49 decimal in ASCII = "1" 
48 decimal in ASCII = "0" 
46 decimal in ASCII = "." 
49 decimal in ASCII = "1" 
or "10.1" 


If you had a hard-coded IP address instead of a hostname for its management host, the logic to resolve the hostname would get confused and attempt to do a reverse-dns lookup of the first 4 characters of the ASCII representation of the hostname, and connect to that instead. So, if your management host was "" the first 4 characters were "10.1" which is

Source  (© 2017, available at, obtained on November 10, 2017) (© 1996-2017 Experts Exchange, LLC., available at, obtained on November 10, 2017)


Additional information

How to Find the Source of Cisco SNMP AuthenticationFailure Traps (© 2017 Cisco, available at, obtained on November 10, 2017)




How SNMP Works (© 2017 Microsoft, available at, obtained on November 10, 2017)


Disclaimer: Please note, any content posted herein is provided as a suggestion or recommendation to you for your internal use. This is not part of the SolarWinds software or documentation that you purchased from SolarWinds, and the information set forth herein may come from third parties. Your organization should internally review and assess to what extent, if any, such custom scripts or recommendations will be incorporated into your environment.  You elect to use third-party content at your own risk, and you will be solely responsible for the incorporation of the same if any.


JS - Archived to 2017November15 - Cleanup

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