I'm experiencing SNMP monitoring issues with my Mikrotik router on PRTG. The error message is: "No response (check: firewalls, routing, SNMP settings of device, IPs, SNMP version, community, passwords, etc.) (SNMP error # -2003)."


This error message indicates that the SNMP packets sent by PRTG are not getting answered. This can have different reasons, for instance:

 
  • The target host is not reachable from the (remote) probe on which the sensor will be added. The fastest check is to add a Ping sensor to the device in PRTG to see if this works properly (if ICMP packets are accepted by the target device).
 
  • Please double check the community string which is configured in the settings of the device in PRTG below the Credentials for SNMP Devices section and that this community string matches with the string configured in the device itself. Please consider that the community string is case sensitive.
 
  • Some devices need an "accepted host configuration" which means, that only particular devices are allowed to access the information via SNMP. Ensure that the address of the (remote) probe is listed correctly in this table.
 
  • If there are any firewalls in between PRTG and the target device, please confirm that the involved firewalls do not block the SNMP traffic. By default, SNMP requires the use of UDP port 161.


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.