ISA problems

[russ]

I am getting random errors while web browsing through my ISA server. The ISA
server is setup up as "caching only" and it doesn't happen all the time,
just once in a while. If i do an NSLOOKUP on the site it resolves the IP
adress ok. Any idea's please.

This is the error

The Web site cannot be found
The Web site you are looking for is unavailable due to its identification
configuration settings.
----------------------------------------------------------------------------
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Please try the following:
Click the Refresh button, or try again later.
If you typed the page address in the Address bar, make sure that it is
spelled correctly.
Click the Back button to try another link.
11001 - Host not found
Internet Security and Acceleration Server
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Technical Information (for support personnel)
Background:
This error indicates that the gateway could not find the IP address of the
Web site you are trying to access.
ISA Server:

regards

Russ