I am trying to establish a connection (using virsh command) to a couple of hypervisor hosts, both on SLES 11.3 environments. The host from where i am making both the connections is a SLES 10.4 instance. *kvmh911351246:~ # virsh -c qemu+ssh://9.113.51.247:22/system <http://9.113.51.247:22/system>libvir: XML-RPC error : authentication requirederror: failed to connect to the hypervisor* The SSH authentication to hypervisor host 9.113.51.247 has already been established. *kvmh911351246:~ # ssh root(a)9.113.51.247 <root(a)9.113.51.247&gt;Last login: Tue Jun 3 11:31:56 2014 from scm-kvmh2-rhel6 SLES11-51-247:~ #* Hence the cause of the authentication failure is not clear. The second connection to another SLES 11.3 host looks like *virsh # connect qemu+ssh://9.121.58.19:22/system <http://9.121.58.19:22/system> bash: socat: command not foundlibvir: Remote error : socket closed unexpectedlyerror: Failed to connect to the hypervisor* where the cause of the error is entirely different. The libvirt packages available on these environments are *9.113.51.247 (SLES 11.3)* *libvirt-cim-0.5.12-0.7.16libvirt-1.0.5.1-0.7.10libvirt-python-1.0.5.1-0.7.10libvirt-client-32bit-1.0.5.1-0.7.10 libvirt-lock-sanlock-1.0.5.1-0.7.10libvirt-client-1.0.5.1-0.7.10* *9.121.58.19 (SLES 11.3)* *libvirt-cim-0.5.12-0.7.16libvirt-client-1.0.5.1-0.7.10libvirt-python-1.0.5.1-0.7.10 libvirt-1.0.5.1-0.7.10* *9.113.51.246 ( SLES 10.4)* *libvirt-python-0.3.3-18.22.1libvirt-devel-0.3.3-18.22.1libvirt-0.3.3-18.22.1* How can these connection failures be debugged? Is there a way to know more information about them?