Recently I switched from dial-up internet to ADSL. When using dial-up I always disconnected the internet when not in use, and I would like to continue this procedure for security reasons. However, if I use the ZoneAlarm Firewall or LAN Connection status box to disconnect the internet I cannot re-establish the connection. Is there another way to re-establish the connection? Also, whenever I attempt to load a PDF file from the web a message appears saying “This page has been blocked”. Is there a setting in ZoneAlarm or Internet Explorer to allow PDF files to be viewed? The computer is running Windows XP.

Without knowing exactly why you cannot re-establish the internet connection, such as any error messages which appear following the manual disconnection, it will be very difficult to offer an explanation and resolution for this problem. However, there are some issues to do with disconnecting the ADSL connection when not in use which you may wish to consider. Broadband internet connections are generally regarded as ?always-on? connections which do not need to be disconnected. This is because most broadband connections operate through a device called a broadband router. I imagine this is the case with your ADSL setup, since you mention the ADSL is connected via the “LAN Connection” on the computer. The broadband router is the device which actually establishes and controls the internet connection. The client computers then connect to the router and are provided with internet access through the router. This has several benefits, the most obvious being that more than one computer can share the internet. However, more importantly, the router provides a firewall between the client computers and the internet, since any inbound traffic from the internet will first be stopped at the router before being forwarded to the relevant computer (in the case of solicited, legitimate traffic) or dropped (in the case of unsolicited or illegitimate traffic). To this end, there is no need to disconnect the internet connection as the broadband router will continue to manage the connection without exposing computers to any great risk. While disconnecting the internet does provide a definite level of security protection, in my opinion for a home connection the benefits are marginal, especially if you already shutdown your computers when not in use. In the worst case scenario, someone could access configuration information on the router, which is quite unlikely in any case given the security implemented on most routers. Additionally, disconnecting an ADSL connection can cause connection problems, such as those being experienced at the moment. Therefore, I would suggest you don’t worry about disconnecting the ADSL when not in use if you have a broadband router. However, should you still wish to disconnect the internet and need to resolve the re-connection issues, then please contact me again with further information regarding the particulars of the problem (such as error messages, and the exact step-by-step procedure you are using to disconnect and re-establish the connection).

Regarding your second question about the “this page has been blocked” messages appearing when attempting to view PDF files, this is an error which I have not experienced. Since the message states the content was blocked, this indicates that software on your computer is blocking the content (as opposed to the problem being caused by other factors, such as network connectivity issues). Both Internet Explorer and ZoneAlarm should not be blocking PDF files, nor should any other security software since this type of file generally does not pose any major security risks for the computer. Of course, you could test this theory by disabling any security software which is running on the computer and then checking whether the problem persists. Before embarking on this procedure, make sure you have enabled the Windows Firewall to provide some basic protection against online threats while your main firewall and security software is disabled. You can enable the Windows Firewall by going to the “Start” menu > “Control Panel” and open the “Windows Firewall” control panel (you may need to first select the “Network and Internet Connections” category). In the Windows Firewall window that appears, make sure the Windows Firewall is “On”. Once you have finished experimenting with the other security software and re-enabled the software, you should disable the Windows Firewall (if the other software does not do this automatically) to avoid any potential conflicts.

Should disabling the security software not resolve the issue, it is possible there is some malware (such as spyware or adware) on your computer causing this behaviour. I suggest downloading and running Ad-Aware Free (www.lavasoft.de), Spybot Search & Destroy (www.safer-networking.org), and Windows Defender (www.microsoft.com/downloads). These three utilities should be able to detect and remove most spyware found on the computer, and thus may resolve the problem. However, if this does not resolve the problem then please contact me again for further advice.