User's Guide
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Version 1.1 User's Guide |
| PICS Administration |
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Once the PICS plug-in is installed and WebDoubler has been launched, you must use WebDoubler's browser-based administration pages to configure PICS and create one or more profiles which block access to certain URLs.
To access WebDoubler's browser-based administration pages, you must have already configured your web browser to use WebDoubler as an HTTP proxy server. See the section "Setting Up Browsers" for instructions on how to set up web browsers to use WebDoubler.
Then surf to the following URL in your web browser:
http://does.not.matter/webdoubler.admin
The server name used in this URL does not matter; WebDoubler will serve its administration pages for any URL where the server name is followed by "/webdoubler.admin".
If this is the first time you have tried to access an administration URL, you will be presented with the standard user authentication dialog for your web browser. Enter the WebDoubler administration username and password. The default WebDoubler administration username is "auric". The default password is "goldfinger".
Once you have entered a valid administration username and password, WebDoubler will display a list of administration pages for all installed plug-ins. Click the link labeled "WebDoubler PICS Administration". You are then presented with a web page which looks like this:
From this page, you can now configure the PICS plug-in to filter content exactly the way you want it to. For a detailed description of all the controls in the "Options" section, see the "PICS Web Admin" section of the "PICS Plug-In Reference", later in this Guide. For now, we just want to make sure that PICS filtering is enabled.
The WebDoubler PICS plug-in lets you create as many profiles as you wish, but only one profile is used to filter each HTTP request. A table listing all of the currently defined profiles is displayed at the bottom of the PICS Administration page. The profile selected to filter a request is called the active profile for that request.
If the WebDoubler Proxy Authorization plug-in is installed, and access to WebDoubler is restricted to certain users, you may select a different active profile for each user. Otherwise, the active profile selected in the PICS Administration page is used for all requests.
Example Profiles
The "Example Profiles" folder installed with the PICS plug-in contains predefined profiles for several common rating services. The quickest way to get started with PICS filtering is often to select one of these profiles and import it. After using an example profile, you will be able to make changes to it or create your own profile.
About the Example Profiles
The rating systems and filters in the example profiles vary widely in how they are implemented and what criteria they use. Example profiles are included for these rating services, and have the filters described below:
The SafeSurf example profile rejects content that has an age range rating of Explicitly for Adults (nine), or if it has a rating of six or higher for sex, nudity or violence and profanity.
Label Bureau: None
The Net Shepherd example profile rejects content that has been rated Objectionable for any age group.
Label Bureau: None
The EvaluWEB example profile rejects content that is rated XC.
Label Bureau: http://calvin.ptloma.edu/~spectre/evaluweb/pics.cgi
The RSAC example profile rejects content that has a rating of four or five for sex, or three or higher for nudity.
Label Bureau: None
The example CyberPatrol profile will reject content that has a non-zero CyberNOT rating for Addiction, Nudity or Sex/Gross Depiction.
Label Bureau: http://pics.microsys.com/ratings/
Importing an Example Profile
The PICS plug-in allows you to import and export profiles using the PICS Profile Manager. To open the Profile Manager, pull down the "Plug-Ins" menu in the WebDoubler application and select "PICS Profile Manager". The Profile Manager window is pictured below:
Click the "New Profile" button in the "Import Into" section to import a profile. A standard open file dialog will be displayed. The example profiles are installed with PICS, and are stored in the "Example Profiles" folder inside the "PICS" folder. Select one of the profiles and click "Open" and the profile just imported will appear in the list of Profiles.
Once the profile is imported, it will appear on the PICS administration page in the "Profiles" section. If there are no other profiles, PICS will automatically activate the newly imported profile. If there is another existing profile, you will have to select the radio button for it and click the "Activate Profile" button to activate the imported profile.
After you have imported and activated a profile, check to see that PICS filtering is enabled. On the PICS administration page in the "Options" section there is a popup menu to enable and disable PICS filtering. When you first start WebDoubler, PICS is enabled by default so you may not need to do anything. If filtering is disabled, select "Enabled" from the menu for "PICS filtering:", then click the "Save Changes" button at the bottom of the "Options" section.
Creating New Profiles
To create a profile, you first must decide what you want it to do. Do you want to prohibit specific web sites from being accessed? Do you want certain sites to always be allowed? Or are you trying to provide broad protection from the millions of unknown, potentially inappropriate web pages out there?
You will need to choose whether you will be using a rating service like RSAC or EvaluWEB, filtering based on the actual URLs, or a combination of the two. Once you have decided what kind of filtering you would like to do, creating the profile in WebDoubler is pretty easy. Just follow these steps:
Click the link labeled "New Profile..." at the bottom of the table of profiles shown in the PICS Administration page. You are then presented with the "Edit Profile" page, part of which is shown below. (Of course, the look of the page will vary somewhat based on your choice of browser and font settings.)
You see sections of the page for each of the three types of information discussed earlier: identifying information, a list of filters, and a list of rating services used by these filters. The name will be "untitled" and the other areas will all be blank since you have just created the profile.
You will want to be able to refer to this profile by name in the future, so fill in the "Identity" fields with information describing the profile you want to create:
When you have finished entering and/or modifying the information in these fields, you must click the "Save Changes" button to save your changes permanently.
Now that you have created a profile, you must add one or more filters to the profile that actually contain the tests used to determine whether web pages are passed or blocked. Filters are the subject of the next section.
A filter defines the criteria used to determine whether each requested URL will be passed or blocked by the PICS plug-in. A profile may contain many filters, each designed to "weed out" different kinds of web pages. Each filter contains one or more tests or URL patterns with the specific criteria that will determine whether the filter is satisfied. A single filter is associated with one and only one profile. It is up to you to create filters to block the content that you decide is unsuitable for your users.
WebDoubler checks every requested URL against each of the filters in the active profile for that request. The list of filters is checked from top to bottom, in order. For each filter, there may be one of three possible outcomes: the page is blocked, the page is passed, or the filter is not satisfied by the request. If a filter is not satisfied, then the next filter in the list is checked. This continues until a filter is satisfied, and the requested URL is then either blocked or passed.
If no filter is satisfied by the request, then the default filter for the active profile is used to determine the outcome. The default filter is at the bottom of the profile page, after the other filters. When you create a new profile, the default filter is set to pass the requested URL. The default filter can also be set to reject requested URLs.
Types of Filters
In WebDoubler, there are two main different kinds of filters that you can create and add to your profiles: URL filters and label filters.
In a URL filter, PICS decides whether the filter is satisfied by comparing the URL of the page with URL patterns defined in the filter. URL filters need only one piece of information to decide whether a page is blocked or not - the URL of the page. Therefore, WebDoubler can make its decision immediately, without having to actually fetch the requested web page from the remote server over the Internet. Using URL filters, therefore, conserves the bandwidth used by WebDoubler for fetching web pages. This makes web pages load faster in your users' browsers.
URL filters are the best solution to use when you know the exact name of a web site whose content should always be explicitly allowed or prohibited. For instance, if you use WebDoubler in a classroom setting, and your school runs a local web server, you can create a URL filter that will immediately pass any web page coming from your school's web server. This filter would come before more complicated filters in the profile's list, to avoid wasting time and thus allowing quicker access to the school site.
Label filters, on the other hand, depend on the rating of the page specified by the PICS labels for the requested page in order to decide whether the filter is satisfied. One or more tests are defined within the filter; each test specifies that the rating of a page must be greater or less than a certain level for the filter to be satisfied.
PICS labels may be either embedded in the header of a web page or fetched separately from a label bureau. Thus, label filters slow down the serving of web pages because nothing will be returned by WebDoubler until the entire page has been downloaded, even for pages that will be blocked from the user. PICS may also have to make a separate connection to retrieve the labels for the requested page from a label bureau.
The advantage to using label filters is that they can be created and then applied to the millions of web pages on the Internet that you are not yet even aware of. So, as your users find new web sites, they will still be protected by the same label filters without the need for you to update WebDoubler with information about those new web sites.
Creating URL Filters
To add a URL filter to a profile, simply click the "New URL Filter..." link in the bottom row of the table under the "Filters" section of the "Edit Profile" administration page, shown below:
A new URL filter will be created, and the "Edit URL Filter" page, shown below, will be displayed.
To finish creating the URL filter, you need to fill out the "Options" section, and then create one or more URL patterns.
Under "Options" are the following fields:
After you modify this information, you must click "Save Changes" for the modifications to take effect.
URL Patterns
A URL pattern determines if a given URL (requested by a WebDoubler user) satisfies the filter. URLs consist of five parts:
Creating URL Patterns
You must create at least one URL pattern for its URL filter to have any effect on requested web pages. To create a URL pattern, click the "New Pattern..." link in the "URL Patterns" table in the "Edit URL Filter" page.
When clicked, your web browser displays the "Edit URL Pattern" page for the new pattern. This page is shown below.
The fields in this page let you enter values for each part of a URL. By default, new patterns are created that match any scheme and any file path.
You must supply at least a hostname in the "Host:" field for a URL pattern to be useful, since all URLs contain a hostname, and a URL pattern with an empty hostname field would only match URLs with no hostname.
A complete description of each field is given below.
ftp://username:password@ftp.someserver.com/
Since WebDoubler does not currently support filtering of FTP requests, you may also choose to leave this field blank. Just to be safe, however, you should enter an asterisk ('*') in this field, which is a "wild card" character that matches any username.
You can create URL patterns that filter URLs using domain names or using IP addresses.
Using Domain Names
A host's domain name, in general, is the text associated with a single, unique web server available on the Internet. For example, the Maxum company web site is served from a host named "www.maxum.com". Domain names use dots to separate the most-specific part of the name from less-specific parts of the name, going from left to right. Therefore, "www" refers to a specific machine in the "maxum" domain, which is a commercial enterprise, thus falling into the generic top-level domain "com" in the USA.
Large companies or companies with large web sites use multiple servers to hold the site's content. Thus, they use many machine names within their single domain. For example, Maxum could run multiple hosts dedicated to each of its products. We would then have domain names like "netcloak.maxum.com", "WebDoubler.maxum.com", and "rumpus.maxum.com".
To match URLs within a single domain, enter the exact domain name you want to filter in the "Host" field. For example, to filter all URLs in the "www.maxum.com" domain, enter "www.maxum.com" in the "Host" field.
An asterisk character ('*') may be used as a "wild card" character at the beginning or end of a domain name. When matching URLs, the asterisk matches zero or more characters. Thus, to match URLs to all of Maxum's hypothetical servers listed above, you could simply create one URL pattern with a host name of "*.maxum.com".
If Maxum also registered the "maxum" domain under other top-level domains, such as "org" or "net", you could filter all URLs whose host name contains "maxum" using a URL pattern with a host name of "*.maxum.*".
Using IP Addresses
Instead of filtering a host by its domain name, you may use its IP address instead. Simply enter the IP address of the host in the "Host" field to create a URL pattern that matches any URL containing the server's IP address.
You can specify that the URL pattern matches a range of IP addresses by appending an exclamation point character ('!'), followed by a "bit mask" value, to the IP address. A bit mask tells WebDoubler how many bits (1 to 32) of the given IP address are significant. Each one of the four decimal numbers in an IP address represents eight bits in the 32-bit integer representation of the address (4 times 8 = 32).
This is useful because IP addresses are allocated amongst machines connected to the Internet in groups which are organized by IP address. Typically addresses are allocated in blocks. Within each block of addresses, all the addresses are the same except for the last eight bits (the last dotted-decimal number). You can create a URL filter which will match any IP address in a particular range of addresses by telling WebDoubler that only the first 24 bits (32 - 8 = 24) are significant. If the block of addresses were in the range "128.227.58.0" through "128.227.58.255", you could enter "128.227.58.0!24" in the "Host" field.
The table below lists common bit mask values to use for common IP address ranges:
| Starting Address | Ending Address | Bit Mask |
| xxx.xxx.xxx.0 | xxx.xxx.xxx.255 | 24 |
| xxx.xxx.xxx.0 | xxx.xxx.xxx.127 | 25 |
| xxx.xxx.xxx.128 | xxx.xxx.xxx.255 | 25 |
| xxx.xxx.xxx.0 | xxx.xxx.xxx.63 | 26 |
| xxx.xxx.xxx.64 | xxx.xxx.xxx.127 | 26 |
| xxx.xxx.xxx.128 | xxx.xxx.xxx.191 | 26 |
| xxx.xxx.xxx.192 | xxx.xxx.xxx.255 | 26 |
| xxx.xxx.xxx.0 | xxx.xxx.xxx.31 | 27 |
| xxx.xxx.xxx.32 | xxx.xxx.xxx.63 | 27 |
| xxx.xxx.xxx.64 | xxx.xxx.xxx.95 | 27 |
| xxx.xxx.xxx.96 | xxx.xxx.xxx.127 | 27 |
| xxx.xxx.xxx.128 | xxx.xxx.xxx.159 | 27 |
| xxx.xxx.xxx.160 | xxx.xxx.xxx.191 | 27 |
| xxx.xxx.xxx.192 | xxx.xxx.xxx.223 | 27 |
| xxx.xxx.xxx.224 | xxx.xxx.xxx.255 | 27 |
| xxx.xxx.0.0 | xxx.xxx.255.255 | 16 |
| xxx.xxx.0.0 | xxx.xxx.127.255 | 20 |
| xxx.xxx.128.0 | xxx.xxx.255.255 | 20 |
Note that URL patterns that specify a host's domain name do not match URLs that refer to the same server by its numeric IP address. Nor do URL patterns that specify a host's IP address (or range of IP addresses) match URLs that refer to a server by its domain name. To be completely secure, you must create two URL patterns, one with the domain name and one with the IP address.
Port(s)
Commonly-used network protocols are assigned a default port number by Internet standards organizations. For instance, the default port number for the HTTP protocol is port 80, and the default port number for SMTP (an e-mail protocol) is 25. The default port number is merely a suggestion; server applications can be configured to use any port number desired by the system administrator.
The port number used by a web server is specified by appending a colon and the port number to the host name in a URL. Thus, a URL for a server listening on port 2537 might look like:
http://www.maxum.com:2537/
You can create URL patterns that match only URLs containing a specific port number. To match a single port number, enter the port number in the "Port(s)" field.
You can also create URL patterns that match a range of port numbers. To do this, enter the starting port number, a dash ('-') character, and the ending port number in the "Port(s)" field. For example, to match all URLs that include port numbers from 17 to 3200, enter "17-3200" in the "Port(s)" field.
If you want to match all port numbers below a given value, use an asterisk character ('*') as the starting port number of a range. For example, "*-3200" would match all port numbers less than or equal to 3200.
Similarly, for matching port numbers greater than a given value, use the asterisk as the ending port number. For example, "17-*" would match any port number greater than or equal to 17.
To match any port number, you must enter a single asterisk in the "Port(s)" field. If you leave the "Port(s)" field empty, the URL pattern will only match URLs that do not specify a port number, so it is best to always enter something in this field.
File Path
The file path portion of a URL consists of everything after the hostname (or port number, if present), including the leading slash ('/') character. For instance, in the URL:
http://www.maxum.com/netcloak/ncdev/releasenotes.text
the file path is "/netcloak/ncdev/releasenotes.text".
To match the URL of a single specific file on a web server, enter the specific path to the file into the "File Path" field.
You may use an asterisk character ('*') at the beginning or end of the file path text to match any string of zero or more characters. Thus, you can match URLs that begin with a certain string, that end with a certain string, or that contain a certain string.
To match a URL that begins with a certain string of characters, add the asterisk to the end of the string. For instance, to match any URL whose file path begins with "/netcloak/", enter "/netcloak/*" in the File Path field.
To match a URL that ends with a certain string of characters, add the asterisk to the beginning of the string. For instance, to match any URL whose file path ends with ".jpeg", enter "*.jpeg" in the File Path field. Use this method to filter out certain file types.
To match a URL that contains a certain string of characters, add the asterisk to both the beginning and the end of the match string. To match any URL whose file path contains "/cgi-bin/", for instance, enter "*/cgi-bin/*" in the File Path field. Use this method to filter out requests for files within a given folder. In this example, we are matching any URL that specifies files within a "cgi-bin" folder.
Quick URL Filters: Using the PICS URL Wizard
While creating URL filters is not a difficult task, the need to filter out certain web sites is such a common one, that WebDoubler provides a better way to set up URL filters quickly and easily. Use the "PICS URL Wizard" to automatically create correctly-configured URL filters to deny (or permit) access to any web site whose domain name or file path contains a given word.
To access the PICS URL Wizard, click the "PICS URL Wizard" link which appears just above the list of profiles in the main PICS administration page, or just above the list of filters in any "Edit Profile" page.
After clicking the URL Wizard link, you will be presented with the PICS URL Wizard page, shown below:
To create a URL filter which rejects URLs containing certain words, enter each word, one at a time, into the text field underneath the "Reject List", and click the "Add Word" button under the "Reject List" to add it to the list. Similarly, to create a URL filter which automatically permits access to URLs containing certain words, enter each word, one at a time, into the text field underneath the "Accept List", and click "Add Word" to add it to the list.
The Accept List takes priority over the Reject List. For example, if "sex" is entered in the Reject List and "essex" is entered into the Accept List, then a URL containing the word "essex" will be accepted, not rejected.
To remove words from the Reject List or the Accept List, select the word from the list, and click the corresponding Remove Word button.
When you have your Reject List and Accept List set up the way you would like, select a profile from the popup menu at the bottom of the page, and, finally, click the "Create Filter" button to create the properly-configured URL filters. WebDoubler will create URL filters named "WebDoubler PICS Reject Word List" and "WebDoubler PICS Accept Word List" in the selected profile.
If you have previously used the URL Wizard to create filters in the profile you select, the words you enter in the Wizard will be added to the existing "WebDoubler PICS Reject Word List" and "WebDoubler PICS Accept Word List" filters for that profile. To edit the word list, click the filter link on the Edit Profile page for that profile and edit the patterns manually.
Rating Services
A PICS rating service is any company or organization which has defined a rating system for categorizing Internet content (typically web pages). Rating services may generate ratings for pages in a variety of ways. A service may have humans review web pages and generate appropriate labels for them, may have automatic software that generates ratings for pages or may apply a list of sites from another organization. A rating service may only define and promote a rating system, depending on page designers or another organization to actually generate the labels for web pages.
Rating services often provide other services which help to ensure that their rating systems are accurately and uniformly applied to Internet content. These include automatic label generators which page designers can use to create PICS labels that can be simply pasted into your web pages, web sites providing further information about their rating systems or label bureaus which dispense ratings for URLs on demand.
Rating Systems
A PICS rating system is merely a set of ratings categories and the defined ratings values within each category. Many PICS rating systems exist on the Internet today, and more are being created every day.
It is important to remember the distinction between a rating service and a rating system. A rating service is a company or organization; a rating system is a set of categories and values created by an organization.
Returning to the movie analogy, the Motion Picture Association of America would be a rating service; the movie ratings categories (G, PG, PG-13, R, NC-17, and X) defined by the MPAA collectively make up a rating system.
RAT Files
In order for a rating system to be usable by PICS-compatible software, like WebDoubler, a rating service must encode its rating system in a text file specially formatted so that it is machine readable. This special file has a filename suffix of ".rat", and is known as a "rating system description file", or simply a ".rat file". These .rat files can then be widely distributed and installed on individual computers. WebDoubler includes .rat files for many of the most popular PICS rating systems used on the Internet, including:
Each of these rating systems defines a set of categories and category values used to rate web pages.
WebDoubler stores .rat files used by the PICS plug-in in the "Rating systems" folder within the "PICS" folder. If you want to filter web pages using a rating system other than the ones shipped with WebDoubler, simply copy that rating system's ".rat file" into the "Rating systems" folder and restart WebDoubler. The new rating system will then automatically become available for use by WebDoubler PICS profiles.
Label Bureaus
A PICS label bureau is simply a web server which returns PICS labels for any given URL, using one or more rating systems, in response to a special HTTP GET request. This special request is called a "label bureau query".
WebDoubler can be configured to fetch labels from a label bureau for any rating system used by each profile. A profile may contain any number of label filters using any number of rating systems and label bureaus, and WebDoubler will perform only the minimum required label bureau queries to check each requested URL.
Fetching labels from a label bureau has advantages and disadvantages which you will want to consider carefully. It causes WebDoubler to execute a second HTTP request for every web page requested through WebDoubler which slows down performance and decreases available bandwidth slightly, even though the response from a label bureau is very small (typically less than 500 bytes).
While there is a performance penalty, using a label bureau provides the most effective content filtering. Label bureaus are constantly updated with information on new web pages, and they provide ratings for web pages that often do not contain embedded labels. Only a small percentage of the millions of web pages available on the Internet today contain embedded labels, so this greatly increases the chances that objectionable content will be properly filtered.
One final comment on label bureaus: there currently are few publicly accessible label bureaus that are available for use and designed to handle large numbers of queries. PICS technical specifications state that the URL used to uniquely identify each rating service should serve as the default label bureau for that service's rating system, but few rating services follow that rule at the time of this printing.
Labels
A PICS label is simply a string of text which tells PICS-compatible software (like WebDoubler):
Different rating systems will have different categories and criteria for the ratings, so labels are specific to a particular rating system.
PICS labels used by WebDoubler are retrieved in one of three ways:
Page designers may determine the rating for their pages and include PICS labels. The labels may be in the pages themselves or may be returned by the web server in the HTTP header for the page. Labels are only fetched from a label bureau when you provide the URL of a label bureau in the configuration settings for a rating service.
Using Rating Services in a Profile
In order to create a profile that filters web pages based on PICS labels, you must define what rating services are used by the profile, and create filters that check the ratings defined by those rating services. When choosing which services to use and what filters to define, keep in mind that ratings and labels are service specific. If a page has labels for one service but you are using a different service for filtering, those labels will be ignored.
Before creating label filters, you must tell WebDoubler what rating services will be used by each profile. To add a rating service to a profile, click the "New Service..." link in the "Services" table in the "Edit Profile" page, shown below.
When clicked, you are presented with the "Edit Service" page, shown below.
At the top of the page, you select which rating service you want to use from the popup menu of available services. This popup menu includes the name of each of the services for which there are .rat files installed in the "Rating systems" folder within the "PICS" folder.
For each service, there are a few options you can specify. First, you can tell WebDoubler whether or not to ignore labels embedded in web pages for this service. This is most often used in conjunction with the second option - the URL of a label bureau to use for this service. If embedded labels are ignored, then only labels fetched from the label bureau are used to evaluate the web page against label filters.
As noted in the text in the "Edit Service" page, consider carefully whether or not you want to use a label bureau. If you do, carefully enter the correct URL for the label bureau in the "Label Bureau" field.
If you decide to use a label bureau, you can specify label bureau options, including the URL of the label bureau, how often to ask it for labels, and what to do when the label bureau does not respond.
When you have configured the service the way you want it, click "Save Changes" for the settings to take effect. To return to the "Edit Profile" page for the profile that uses this service, click the "Edit Profile" link at the top of the "Edit Service" page.
Creating Label Filters
Once you have specified at least one rating service to be used by your profile, you are ready to create a label filter.
To create a label filter, click the "New Label Filter..." link in the table of filters at the bottom of the "Edit Profile" page. The "Edit Label Filter" page is then displayed:
To finish creating the label filter, you need to fill out the "Options" section, and then create one or more label filter tests.
Under "Options" are the following fields:
Whenever you modify this information, you must click "Save Changes" for the modifications to take effect.
Label Filter Tests
A label filter test defines a comparison to be made against all PICS labels that are found by WebDoubler for the requested page. The result of a test is either true or false. If the result of a test is true, the requested page is said to "pass" that test. The filter can be configured so that if any or all of the tests pass or fail the page will be accepted (allowed) or rejected (blocked). This sounds very confusing, but gives you a great deal of flexibility when defining filters. Say, for example, you wanted to block pages with nudity. To make the filtering more reliable, you decide to use three different rating services. After specifying the rating services you would like to use in the profile, you could define a filter with three tests. Each test would check for a nudity rating higher than acceptable from one of the three services, and the filter would be defined so that the request would be rejected (blocked) if any of the tests passed (if the page was rated higher than acceptable according to any of the three services).
Creating Label Filter Tests
To create a label filter test, select a rating service from the popup menu, then click the "New Test..." button. To edit an existing label filter test, click the "Edit Test..." button next to the existing test in the table.
The list of rating services in the "Test Service" popup menu includes all of the rating services you have configured for the current profile.
When you click "New Test...", you are shown the "Edit Label Filter Test" page, pictured below. The look of this page will vary based on which rating service you select. This example uses the RSAC service.
The top of the page includes the name of the selected rating service and a brief description. The "Test Criteria" section includes a popup menu of comparison operators, and a table of categories and category values (listing a name, a description, and an optional icon for each category and value) from the selected service's rating system.
To define a test, select a comparison operator from the popup menu, choose which category to test (by clicking its radio button), and finally, pick the value within that category (by clicking its radio button). Finally, click "Save Test" to save the test settings.
How do you decide which comparison operator and which category/value to choose? It depends on the "action" you selected for the label filter. If you create a filter which is designed to "reject" pages that pass its tests, then you generally want to create tests for pages whose ratings are "greater than" or "greater than or equal to" some upper threshold value. If you create a filter designed to explicitly "accept" pages, then you usually create tests that check that a page's rating is "less than" or "less than or equal to" the upper threshold value. This is generally the case because most rating systems define categories and values such that lower values are less objectionable, while higher values are more objectionable. For example, the RSAC rating system defines a "Sex" category with a value of zero for "No sexual content" on up to a value of 4 for "Explicit sexual activity; depiction of sex crimes".
When you have saved changes to the label filter test, click the "Edit Label Filter" link at the top of the page to return to the Edit Label Filter page for this label filter, or click the "Edit Profile" link to return to the Edit Profile page for this filter's profile.
Changing the Order of Filters
Whenever you create a new filter, WebDoubler automatically adds that filter to the end of the list of filters within a profile. Because filters are checked in the order that they are listed, it is important that you be able to rearrange this list to suit your needs.
In particular, for best WebDoubler performance, you should always list URL filters before label filters. This is because URL filters can be checked before the requested web page is actually fetched from the remote web server over the Internet. If the page is rejected by the URL filter, the no access page will be returned to the user immediately without waiting for the page to be retrieved from the Internet.
To change the order of filters within a profile, enter new values for each filter in the "Index" column of the filter table, then click the "Change Order" button. WebDoubler will reorder the list of filters from lowest index to highest index.
Deleting Filters
To permanently delete any filter from a profile, select that filter's hypertext link from the filter list in the "Edit Profile" page, then click the "Delete Filter" button at the bottom of that filter's "Edit Filter" page. Be sure that you really want to delete the filter, because a deleted filter is permanently deleted and this command is not undoable.
Statistics
The main PICS administration page displays the current count of passed URLs, blocked URLs, and the relative percentage of each compared to the total number of requests processed through WebDoubler.
Logging Blocked URLs
To enable logging of blocked URLs by the PICS plug-in, change the "Log Blocked URLs" setting under "Options" in the PICS main administration page to "Enabled", and ensure that a valid file path is entered in the "Log File Name" text field. Click "Save Changes" for logging to begin.
When enabled, the PICS plug-in will add a line to the specified log file every time a requested URL is blocked. The log line is in a tab-delimited format and includes:
The PICS blocked URL log is in a format that is compatible with any log file analysis software that can parse WebSTAR log files.
Every time WebDoubler is relaunched, a startup line is written to the log file which records the date and time of the launch and describes the log file format.
Selecting the Active Profile
When multiple profiles have been created, you can tell WebDoubler which profile to use to filter incoming requests by defining the active profile. Only one profile is active at any one time.
To activate one of the defined profiles, click the radio button in the "Active" column in the table of profiles in the main PICS administration page, then click the "Activate Profile" button. The profile is activated immediately.
Assigning Profiles to Users
If the Web Doubler Proxy Authentication plug-in is installed and enabled, then you may configure WebDoubler to apply a different profile for each authorized user account. This is the one exception to the "only one active profile" rule.
To assign a profile to an individual authorized user using the Web administration interface:
You can also assign a profile to an individual authorized user in the WebDoubler application:
Sharing Profiles and Filters
Because creating effective PICS profiles and filters is a time-consuming process, we have made it easy for WebDoubler users to share profiles and filters. WebDoubler can import and export profile and filter information in a common, cross-platform, plain-text file format called "PICSRules". Thus, WebDoubler profiles and filters can be shared with other WebDoubler users and any other PICSRules compatible product on any hardware platform.
Over time, many useful filters and profiles will be developed by WebDoubler users. The best of these profiles can be exported, uploaded, and posted on Maxum's web site so they can be shared with other WebDoubler users.
Import and export of profiles and filters is performed using the "PICS Profile Manager" window in the WebDoubler application, shown below.
Exporting Profiles
To export a profile, select it from the "Profiles" list, then click the "Profile" button in the "Export" group. A standard Save File dialog box is displayed. Navigate to the folder where you want the exported "PICSRules" profile file to be saved. Enter a name for the file in the text field, then click the "Save" button.
Importing Profiles
To import a profile from a PICSRules formatted text file, click one of the two buttons in the "Import Into" group.
Click the button labeled "New Profile" to import the profile into a brand-new profile. The new profile's name will be added to the list of profiles displayed.
To append the filters and services defined in an imported profile to one of your existing profiles, select the profile you want to append to in the list, then click the button labeled "This Profile". The filters in the imported profile are added to the end of the filter list in the selected profile, so you may need to change the order of the filters when the import is completed.
In either case, when you click the appropriate button, you are presented with a standard Mac OS Open File dialog box. Navigate to the folder containing the profile file, select the file and click "Open".
Exporting Filters
Instead of exporting an entire profile, you may instead export a single filter from within one of your profiles. The "PICSRules" file that is generated defines a profile containing just the selected filter.
To export a single filter, select the profile containing the filter from the "Profiles" list, then click the "Filter" button in the "Export" group. A list of the filters in that profile is displayed:
Select the filter to be exported, then click the "OK" button. A standard Save File dialog box is displayed. Navigate to the folder where you want the exported "PICSRules" profile file to be saved. Enter a name for the file in the text field, then click the "Save" button.
Deleting Profiles
To permanently delete any profile, select that profile's hypertext link from the PICS administration page, then click the "Delete Profile" button at the bottom of the "Edit Profile" page. Be sure that you really want to delete the profile, because a deleted profile is permanently lost, and this command is not undoable. When you delete a profile, you delete the profile, all the filters contained in that profile, and the rating service definitions used by that profile.
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