I am fairly certain that permissions are negotiated only once during the mount, or the beginning of the CIfs transfer (in the case of \\copy\to\UNCname). Again, I would have to take a look at the CIFs and openEX docs. I left MS in 2003/2004, so my recollection is not the best. Most file transfer protocols authenticate once and grant the client some sort of token which is reused (rcp). Some re authenticate once per event. Very few protocols reauthenticate/renegotiate repeatedly, for example, once per 64k transferred. This excludes some of the ultra-reliable message/file queuing software out there (ntm and mqube).