What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

SNMP error # -2003



Everytime I try to set up a sensor to one of our MPLS locations the sensor is failing and I am getting this error. I have a trial version setup on another machine that can access the unit just fine. On my production machine I am able to access other SNMP locations without any trouble.

The machine does not have the local firewall enabled, the UDP 161 port is opened on our main firewall, I am selecting the correct verison, IP address is correct and the Community string is accurate.

At this point I am stuck, I do not know what else to try.

error prtg snmp

Created on Jun 28, 2010 5:41:28 PM

Last change on Jun 29, 2010 2:09:18 PM by  Daniel Zobel [Product Manager]

7 Replies

Accepted Answer



Common SNMP Errors

In case of SNMP Error -2003, please refer to the article My SNMP sensors don’t work. What can I do?

You will find a possible explanation for this error message there.

Use SNMP Tester

Also, try to connect using our SNMP Tester. Please refer to the article How can I test the functionality of my SNMP device?

Created on Jun 30, 2010 2:58:09 PM by  Patrick Hutter [Paessler Support] (7,225) 3 3

Last change on Oct 8, 2013 4:25:52 PM by  Gerald Schoch [Paessler Support]



We had the -2003 error, but not with installing sensors. It happend after a few days. After changing the timeout value from 5 tot 30 seconds, this all went away.

Created on Mar 23, 2016 7:24:00 AM



Hi there,

PRTG supports paging for SNMP requests since PRTG Version 16.1.22. This will improve the stability and might also help to prevent SNMP #2003 errors.

Basically, the #2003 sensor indicates that the requests ran into a timeout, this might happen due to an overload of the target device which might lead to a lower prioritization for SNMP packets. Raising the timeout value, or even the scanning interval might help in these cases.

Best regards, Felix

Created on Mar 23, 2016 8:18:32 AM by  Felix Saure [Paessler Support]



Dear Support,

We also received "SNMP error # -2003" errors using the default SNMP System Uptime sensor. After changing the "IPv4 Address/DNS Name" setting from the DNS hostname to the IP address, the sensor worked fine. Other sensors like PING were working fine with DNS hostname. Could there be an issue with SNMP sensors using DNS hostname?

Regards, Hendrik-Jan

Created on Mar 28, 2018 9:44:56 AM



Hi there,

We are not aware of any problems in this regard. I also just tested a SNMP sensor with the DNS name configured, which worked just fine.

Does this happen also when using our SNMP Tester? https://www.paessler.com/tools/snmptester

Please refer to this article for more information about how to use it: https://www.paessler.com/tools/snmptester

Kind regards,
Andreas Günther, Technical Support

Created on Mar 29, 2018 7:31:55 PM by  Andreas Günther [Paessler Support]



I have some strange behaviour connected to SNMP error 2003:

The server (linux) that I am trying to get information from is customer-facing; SNMP is active on the server, and an snmpwalk on the server gets results. The PRTG server gets information from other machines just fine. Neither the main firewall of the network nor the one on the linux machine are blocking snmp to/from this server But the snmp tester throws an error 2003.

Created on May 7, 2021 10:21:23 AM



If the SNMP Tester throws the error 2003, this means that the PRTG server did not receive any response from the target device. So either there's still something blocking the network (a wireshark capture for example might help here) or the PRTG server is not allowed to query it. Please double check the SNMP access rights in the device. (The IP of the PRTG server must be configured in the target device's configuration to be an allowed host. This is a "rudimentary" security feature of SNMPv2, since it's unencrypted).

Created on May 10, 2021 11:34:00 AM by  Timo Dambach [Paessler Support]

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.