Filtering by Specific IP Addresses May Not Be Effective (170251)
The information in this article applies to:
- Microsoft Proxy Server 1.0
- Microsoft Proxy Server 2.0
This article was previously published under Q170251 SYMPTOMS
Enable filtering for Web Proxy and Winsock Proxy services by specified IP
address may not work effectively.
CAUSE
Filtering by specified IP address may not work effectively because several
IP address may answer for a given domain name. If you pick one address, you
will miss the other addresses that mirror the same server content.
Also in some networks, IP addresses may be dynamically assigned by using
Bootstrap Protocol (BOOTP) or Dynamic Host Control Protocol (DHCP)
services. When BOOTP and DHCP are in use, the remote server's IP address
may change.
WORKAROUND
Apply filtering based on DNS Domain names for specific sites.
MORE INFORMATION
If you manage a large private network that uses TCP/IP but does not connect
to the Internet, you may find it easier to precisely filter access by
entering specific IP addresses.
Although DNS filtering is easier to manage and generally preferred where
available, listing individual IP addresses for filtering is a valid option
where DNS naming services are not managed on your network, and your private
network uses static IP addressing.
| Modification Type: | Major | Last Reviewed: | 8/11/1999 |
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| Keywords: | kbother KB170251 |
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