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Home > Success Center > Network Configuration Manager (NCM) > NCM - Knowledgebase Articles > NCM Error: Connection Refused by A.B.C.D

NCM Error: Connection Refused by A.B.C.D

Updated March 11th, 2016


This article describes the issue when a Telnet/SSH session is being established between NCM and an end device, but the connection is refused. The error is seen either under the Node properties page as: 

Test failed. Connection Refused by A.B.C.D


or when initiating a configuration backup as:

Transfer Status: Connection Refused by A.B.C.D


where A.B.C.D represents the IP of the end node.


All versions of NCM


Scenario 1: Environmental issue

Common causes:

  • Traffic flow not allowed
  • Telnet/SSH services are not configured correctly or services not enabled
  • Wrong credentials
  • Lack of privileges
  • Access lists not allowing traffic to or from the NCM server


Scenario 2: Issue on the Orion/NCM side

Common causes:

  • Wrong credentials
  • Wrong protocol/protocol version/protocol port
  • Wrong device template
  • Command in the selected device template is not correct for the device giving the error
  • Allow Terminal Server Support and /or Use Keyboard Interactive Authentication may be set to 'Yes' when they should not be

A connection refused error can be sent by NCM even if the Vty session is established. This could be thrown because of time outs by the device or an NCM timeout.


Scenario 1

In order to rule out any of the mentioned causes, try to connect to the device by using a Telnet/SSH client (like Putty (© 2017 Simon Tatham ©, available at, obtained on March 21, 2017.)) from the Orion server; or more precisely from the Polling Engine to which the node is assigned.

Make sure you use the same credentials as configured in NCM.


Case 1: You cannot establish a connection and get the same Connection refused error:

  • Engage your networking team to check the firewalls (both hardware in the network, or software running on the server) and other networking devices that might be blocking the traffic with an access list (routers, switches, etc.).
  • Check if the required Telnet or SSH service and version are properly configured and enabled on the device.
  • Make sure the user account used by NCM has sufficient privileges to not only connect to the device, but at level to execute the commands to perform the task.


Case 2: Connection successful.

If you managed to connect successfully proceed with troubleshooting by following the steps in Scenario 2.

Scenario 2

Since it has been confirmed that the traffic flow is allowed and all the settings are in place on the device, make sure everything is properly configured on the NCM side:

  1. Edit the Node, and check the NCM related settings.
  2. Select the node > click Edit Node > scroll down to NCM Properties, check the following:
    1. Switch to "No Profile" under Global Connection Profile.
    2. Use the same Username and Password as you used during Scenario 1. If applicable fill in the Enable Level and Enable Password details.
    3. Hard-code the "Execute Scripts Using", "Request Configs Using" and "Transfer Configs Using" to the protocol you used in Scenario 1.
    4. Set the telnet and SSH ports to 23 and 22 respectively.
    5. Hard-code the appropriate template under: Device Template.
    6. Verify the command in the the device template is the correct command, if not you will probably be better off creating a duplicate of the template used and modifying the command and then use it.
    7. Click Test.
      Note: The Test can give you a false positive or false negative result. We recommend trying to initiate a backup regardless of the outcome of the test.
    8. Click submit and initiate the configuration backup once again.

Scenario 2A

In NCM 7.5.1 after the installation or upgrade, it has been rarely seen when using the same credentials with Putty and the NCM Connection tester tool is successful, but accessing from the NCM application is not working.

  1. Check the NCM logs at C:\Progamdata\solarwinds\logs\orion\NCM\Preinstaller.
  2. If this file is not present or has not been updated with current installation or upgrade date, the installation was not successful.
    1. Reboot the NCM server.
    2. Uninstall the NCM-NPM v7.5.1 Integration Module. (Cancel the Configuration wizard when it pops up.)
    3. Uninstall The Network Configuration Manager v7.5.1.
    4. Reinstall NCM with Adminstrator Rights.


Note: If you followed all the steps from both scenarios and the issue still persists collect a session trace log file with the issue reproduced and submit a ticket to the SolarWinds Technical Support to get further assistance.


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.


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