SSRS CROSS Domain Reports Server Authentication
I don't recommend it but  

You have two options:


Connect using a domain username &amp; password from network A (everyone
in network B connecting as DOMAINA/userx)
Allowing anonymous access.  (this is inherently dangerous and you would want at a bare minimum to pass something to all of your reports as part of your process for security authentication and probably change the default structure for uploading http://local/reportserver might become http://local/rs)