This article applies as of PRTG 22
When monitoring vSphere Hypervisor (ESXi) version 5.1 or higher, occurs an error message:
"The underlying connection was closed: An unexpected error occurred on a send", preventing VMware monitoring. Is this a known issue, and how to resolve it?
Monitoring ESXi 5.1 and higher: Handshake failure on Windows XP/Server 2003
vSphere Client 5.1 and higher only accepts connections that use strong cipher suites. Since Windows XP and Windows Server 2003 do not use these, the client cannot connect to the server due to a handshake failure.
For the same reason, you may encounter similar problems if your probe runs on Windows XP or Windows Server 2003 and you want to monitor ESXi 5.1 or higher via SOAP sensors.
Note: Running PRTG on Windows XP or Windows Server 2003 is not officially supported.
For details about this handshake failure and possible workarounds, refer to the VMware Knowledge Base:
- vSphere Client and vSphere PowerCLI may fail to connect to vCenter Server 5.5 due to a Handshake failure (2049143)
- VMware vSphere 5.1 Release Notes
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.