Multiple connection refused alarms from RHEL 6 servers (RSP probe) - Access denied for 'none'.

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)

Issue/Introduction

The RSP probe triggers "Connection refused" or "Access denied for 'none'" alarms when monitoring RHEL 6 servers, even when credentials and SSH configurations are verified as correct. Log entries may indicate the probe is attempting authentication but failing or timing out before completion.

Environment

• DX Unified Infrastructure Management (UIM)
• RSP (Remote System Probe) version 5.58 and later
• Target OS: Red Hat Enterprise Linux 6 (RHEL 6)

Resolution

 Adjust the RSP probe timeout settings to allow additional time for authentication:

1. Launch the OC and edit the MCS Setup RSP (Enhanced) profile on the robot hosting the rsp probe
2. Locate the Command Timeout (Seconds)
3. Increase the value from the default 30 seconds to 60 seconds.
4. Save and apply the changes to the probe configuration.
5. Monitor the rsp.log to confirm the probe successfully completes the authentication handshake with the target RHEL 6 servers.

Note: If connection issues persist after increasing the timeout, verify if your environment requires the explicit enablement of legacy SSH algorithms (KexAlgorithms and HostKeyAlgorithms), as documented in existing RHEL 6 compatibility guidelines.