Hi Eric, thanks for reply My netcat version is v1.10-38 and I am using Debian on 192.XXX.XXX.XX # nc -h [v1.10-38] connect to somewhere: nc [-options] hostname port[s] [ports] ... listen for inbound: nc -l -p port [-options] [hostname] [port] I use Ubuntu to access the Debian machine, and now my Java class is like this: public static void main(String[] args) { Connect conn = null; try { conn = new Connect("xen+ssh://root@192.168.XXX.XX/?netcat=/bin/netcat", true); but is still throwing the error: libvir: RPC error : End of file while reading data: /bin/netcat: invalid option -- 'U' nc -h for help: Input/output error exception caught:org.libvirt.LibvirtException: End of file while reading data: /bin/netcat: invalid option -- 'U' I have files on the client machine that are /usr/bin/ncat , /bin/netcat and /etc/alternatives/netcat. I am not sure which I should use. Thanks, Felipe <div class="gmail_quote">On Tue, Oct 2, 2012 at 12:27 PM, Eric Blake <<a href="mailto:eblake@redhat.com" target="_blank">eblake@redhat.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On 10/02/2012 09:10 AM, Felipe Oliveira Gutierrez wrote: > Hi, > > I am using java to connect to the xen, but my class is throwing a > exception. Does anyone know what is happening? > > public class TestConnection { > public static void main(String[] args) { > Connect conn = null; > try { > conn = new Connect("xen+ssh://root@192.XXX.XXX.XX/", true); > > libvir: RPC error : End of file while reading data: nc: invalid option -- > 'U' </div>What distro is running the machine at 192.XXX.XXX.XX, and what version of nc is it using (remembering that Fedora and Debian nc come from different heritages)? What does 'nc --help' output on that machine? It may be possible to connect by installing an updated nc on that machine, and/or altering your xen+ssh://... URI to include a ?netcat=... parameter that points to an alternate location on that server that understands -U. <a href="http://libvirt.org/remote.html#Remote_URI_parameters" target="_blank">http://libvirt.org/remote.html#Remote_URI_parameters</a> -- Eric Blake <a href="mailto:eblake@redhat.com">eblake@redhat.com</a> <a href="tel:%2B1-919-301-3266" value="+19193013266">+1-919-301-3266</a> Libvirt virtualization library <a href="http://libvirt.org" target="_blank">http://libvirt.org</a> </blockquote></div> -- <div>-- Felipe Oliveira Gutierrez</div> <div>-- <a href="mailto:lipe.82@gmail.com" target="_blank">lipe.82@gmail.com</a></div> <div>-- <a href="https://sites.google.com/site/lipe82/Home/diaadia" target="_blank">https://sites.google.com/site/lipe82/Home/diaadia</a></div>