Do ISP's block network resource traffic?

When I am at home I cannot use 'net use' , 'net view' or any of the resources.(The error I get is System 53)
They work fine on my internale subnet actually its just wehn I attempt to go beyond the router.
When I am at work these work fine but we are on the business line of the same porvider.

I was thinking maybe they block this (Cox in Southern California) to prevent spammers from abusing 'net send'
but I cannot seem to find any information about it on my providers web site.


Anyone familiar with this?