Q: Why xmllint can't find xmldsig-core-schema.xsd? I want to validate my XML file against some XSD file so I do this in terminal:
xmllint --schema IR-1/schemat.xsd IR-1/dokument.xml --noout

but this, after some time, gives me error:

http://www.w3.org/TR/xmldsig-core/xmldsig-core-schema.xsd:1: parser error : Document is empty
  IR-1/schemat.xsd:15: element import: Schemas parser error : Element '{http://www.w3.org/2001/XMLSchema}import': Failed to parse the XML resource 'http://www.w3.org/TR/xmldsig-core/xmldsig-core-schema.xsd'.
  WXS schema IR-1/schemat.xsd failed to compile

Why  can't xmlint download http://www.w3.org/TR/xmldsig-core/xmldsig-core-schema.xsd?
Is this has something to do with w3c adding additional timeouts when serving those files?
How can I cache this file or extend time of connection timeout for xmllint?
