Accessing client PC from a web service

[its_me_]

Hi, I am new to this post. This question may not be a good one. but still..Can a web service gain access to the client PC that calls the web service? For example, can a web service access the registry of the client PC and read from it? Is it allowed in web service ethics? Clients normally consume web services for getting something done. Here, I need to call a web service to get the web service to do an action on my PC like reading my registry. Is it possible?

[Marten Deinum]

No... A webservice knows nothing of the client (nor should it) it only receives a messages and acts upon that...