More Information > Security and Error Handling

There are advantages to placing a system in a network that is in front of the search appliance.

This system can provide additional functions that are not part of search, yet may be useful when running a network service. The following sections discuss two benefits that an additional system can provide.

Firewall Capabilities

If you isolate the search appliance behind a firewall, you can selectively block access by using any of the following methods:

• Block access to the Admin Console on port 8000, so that users can only get to the Admin Console on port 8443 (which uses HTTPS).
• Restrict access to the search appliance based on end users' IP addresses.
• Prevent a Denial of Service attack.

Error Handling

The search appliance is designed to correct its own problems. In rare cases, however, users can get an error from a search request. You can control how these errors are presented to a user with a script that runs on your web server.

The script can work in the following way:

1. Users send a search request to the script.
2. The script formats the request and sends it to the search appliance.
3. The system sends the response back to the web server, which processes the results before sending them to the user.

The following examples provide strategies for handling errors in a script:

• If the HTTP status code of the response is 200, no error has occurred. Send the results back to the user.
• If the HTTP status code is 500, then an unexpected error has occurred. The script can retry the search request or send an error to the user.
• If the HTTP status code is 404, the user has requested a URL that does not exist. Send an appropriate error message to the user.
• Set a timeout in your script. If the system does not respond within the specified time, the script can attempt to ping the search appliance. If the ping fails, then send an error to the user. If the ping succeeds, then retry the search request once more. If the search request fails, send an error to the user.

For More Information

For information on search appliance network planning, see "Planning for Search Appliance Installation," which is linked to the Google Search Appliance help center.