We use IIS 4.x for our local intranet. In IIS the "NT Challenge Response" check box is checked, and no other is checked. We have been experiencing server slow downs recently (about 45 users max). In looking at the IIS log files I found that a lot of the time when a client browser made a request IIS returned a code of 200 ("success"), after that (3secs later)in the log file, for the same page and client browser there is a "401" entry("access denied"). In looking at the statistics over a working day. I find that approximately 5% of pages in the log file have "401" errors in the log file. Can anyone shed in light on this.<BR>