Note: The following is adapted from "Kill The Banners", written by Robert Basler, which appeared in OS/2 e-Zine! in the June 1999 issue. This adaptation was published in SCOUG's newsletter, OS/2 For You  in March 2000.

Looking for a way to block undesired banner ads on web pages (especially in the wake of the recent DoubleClick controversy)? (And, for that matter, speed up the downloads of the pages you do want to see?) Or do you want to block your children from seeing websites they really shouldn't see? Or both?

Here's an easy way of accomplishing the task, for free, without having to install any new software!

1. If not already in your CONFIG.SYS, add the following line: SET USE_HOSTS_FIRST=1

2. Edit (or create) x:\MPTN\ETC\HOSTS (where x is your OS/2 boot drive): Add the following for each website that you want to block access to: 127.0.0.1 ad.doubleclick.net 127.0.0.1 ad.usatoday.com (and so forth. Beware: ad graphics that are loaded from the same domain(s) as the sites you DO want to see, such as www.os2ss.com, will still be displayed).

   You can even use the same coding to block access to websites such as Barney, Playboy/Penthouse, Pokemon-related sites, etc. Make sure the last line in your HOSTS file is terminated with a CR/LF (carriage return/line-feed) pair, or else the last line will not be processed.

3. If you had to alter CONFIG.SYS, you will need to reboot for the changes to take effect.

How does it work?

When TCP/IP needs to load a graphic, such as a banner advertisement on a web page, quite often those graphics will come from one of many standard sites that service web sites throughout the Internet. One such site is "ad.doubleclick.net". By making the above changes, OS/2 will not be able to find these sites and thus will not load the banner pages.

The HOSTS file is used when TCP/IP needs to look up a computer, a host, like www.scoug.com on the Internet. Usually with OS/2, the TCP/IP stack looks to your ISP's domain name server (DNS); then, if that doesn't have the host you are looking for (or the DNS is unavailable), to the HOSTS file. This is bad if you don't want to load undesirable banner ads (or objectionable web sites) because your ISP's domain server usually knows where these hosts are. The CONFIG.SYS change described above forces TCP/IP to look into the HOSTS file first, then to the DNS server.

In the HOSTS file, the IP address 127.0.0.1 is the IP address used in the loopback interface (or in other words, a dummy IP address), and the domain name listed is the one(s) you want suppressed. This way, Netscape will not be able to find the referenced graphic and will display nothing, or one of those "broken link" graphics.

And if it's one of those websites you don't want your children (or yourself or someone else) to see, Netscape eventually times out with the message "There was no response. The server could be down or is not responding. If you are unable to connect again later, contact the server's administrator".

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