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I can connect to my switch via SNMP in Paessler SNMP Tester 5.1 but when I put in the same credentials into PRTG this errors shows up.


Any ideas?

error prtg snmp

Created on Aug 20, 2013 2:25:05 PM

4 Replies




thank you very much for your KB-Post. May I ask, which exact version of PRTG are you running?

best regards.

Created on Aug 21, 2013 9:06:23 AM by  Torsten Lindner [Paessler Support]



Hi Torsten,

I have the same issue after upgrading to v13.3.4.2557. I am trying to authenticate with a new Cisco 3925 router using SNMP v3 w/ MD5 and no encryption.

I get the same error message: SNMPERR_AUTHENTICATION_FAILURE (SNMP error # -35)

At first it PRTG didn't like my password being less than 8 char in length.

Created on Aug 30, 2013 6:32:37 PM



Could you try updating to the newest version to see if that resolves the issue?

If the newest version ( isn't available for the auto-update you can download the software from the shop.

In order to access the download link to the newest version you have to log into your online account and download it there.

Please use the email address the license is registered to and your password to log in here: https://service.paessler.com/en/login/

Once you have downloaded the newest version there, you can install it directly over the version currently running. The configuration and database will not be affected by installing the newer version over the old and the configuration is automatically backed up before this process.

Created on Sep 2, 2013 12:52:58 PM by  Greg Campion [Paessler Support]



I updated and this problem was fixed. I think it had something to do with PRTG only allowing DES not Triple DES.

Created on Sep 2, 2013 12:54:53 PM

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.