If you are like the majority of Microsoft Proxy Server users, you will most likely be using a periodic dialup connection to gain the Internet connection used by LAN users. Most Internet Service Providers offer many online hours for a flat fee. Some even offer "unlimited" access. If you put them to the test by keeping your computer on and online all the time, they tend to get testy. Therefore, you need a way of automatically connecting the NT server running Microsoft Proxy Server to the Internet when a proxy client makes an Internet request. The Auto Dial configuration utility, found in the Microsoft Proxy Server folder, is the application that will allow you to set up the RAS entry to dial and the times which the Microsoft Proxy server is permitted to dial out. Figure B.1 shows the location of the Auto Dial utility.
The Auto Dial utility is very easy to configure. You need to indicate which hours Microsoft Proxy Server is permitted to dial out to the Internet and which RAS account should be dialed. This necessitates that you have RAS installed and at least one ISP account configured within RAS.
WinSock Proxy client requests will always force Microsoft Proxy Server to initiate a dial out to the Internet if Auto Dial is enabled. Web Proxy client requests will only initiate a dial out if the requested information cannot be found in the Web Proxy cache. Some clients may time out before Microsoft Proxy Server can finalize the Internet connection. A dial out connection can take up to a full minute to negotiate. However, most of the time Microsoft Proxy Server should simulate a successful connection to a target server until the Auto Dial connection is established. This means that if the connection cannot be made, the client application will not respond with a Site Not Found error, but rather a No response from server error.
Figure B.2 shows the Auto Dial utility.
To enable Auto Dial, simply check the Enable Dial on Demand check box. By default all times are permitted for Auto Dial. If you need to remove certain time slots from Auto Dial, simply click a time block, hold down the left mouse button, and drag the pointer to the end time. Blue indicates allowed Auto Dial and White indicates when no Auto Dial is permitted.
Clicking the upper left-hand corner of the time chart allows you to select all times. You can also click on the days or the hours to enable/disable entire blocks at once. The Credentials tab allows you to select a RAS entry to dial when Internet requests are received and what logon name and password to use. Figure B.3 shows the Credentials tab.
Any RAS phone book entry can be selected from the Entry Name drop down list. The User Name and Password fields can be used to indicate the username and password to use when logging on to the selected provider. If the selected provider is another NT system, the Domain field can be used to indicate which domain on the target network the logon credentials should be presented to for validation. This field should be left blank if the selected entry is a traditional UNIX host.
Once you have completely configured the Auto Dial settings, you can click OK (or Apply). The WWW service and the WinSock Proxy service should be stopped and then restarted in order for Auto Dial to be enabled. Stopping the WWW service also stops the Web Proxy service because the Web Proxy service runs as a sub service to the WWW service. The WinSock Proxy runs on its own without any reliance on the WWW service. To start and stop these services use the Internet Service Manager, which can be found in either the Microsoft Internet Server or the Microsoft Proxy Server folders. The WinSock Proxy service and the WWW service can be stopped and started in any order.
Auto Dial allows the Microsoft Proxy Server to establish connections to the Internet when needed and can help keep costs down without LAN users ever knowing that the network does not have a constant connection to the Internet. Most providers will disconnect a connection after 10 to 15 minutes of inactivity. Auto Dial will reestablish the Internet connection when needed.
Auto Dial is a necessary element of any proxy server. Many UNIX-based proxy servers do not have Auto Dial ability, and they do not have the ability to support non-CERN-compatible clients. Microsoft Proxy Server will help keep your connection costs down while providing full time Internet access.