Do we need to have INTERNET connection when we reference...

Hi,

Just wondering whether we need INTERNET connection when we reference the name spaces like 

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"

in any of the XSL or XSD documents?

I tried removing the LAN connection and tried with a VB executable to transform XML to XML document with XSL. It worked!!!!

Can I say that we just need to have the above string in the document? or do we really need internet connection?

Thanks,
Ravi