Library Technology
Methods of Filtering
Web Filtering
Web filters review every request for web pages and other computer resources, then then block anything that is unauthorized. Web filters do this by a combination of the following methods:
- Address filtering - blocking on the basis of lists (often secret) of internet addresses.
- Keyword filtering - blocks pages based on a check of a banned words list.
- Filtering by service / format of content - blocking video/audio streaming, IM clients, etc, even if the surrounding page is passed by the web filter.
- Allowlisting/Whitelisting - Build a list of approved sites, often block anything not on approved list
Most web filtering software allows blocking of sites by subject categories using a mix and match of the methods above.
Domain Name Service (DNS) Filtering
DNS filtering works by routing your computer's "domain name" requests through a filtering provider. That provider uses the address to decide whether to provide the page to your computer.
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What is DNS and how does it work? (TechRadar, Sept 2021)Overview of what Domain Name Service is. Updated January 2024.
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Configuring OpenDNS on your deviceAn article explaining how to use OpenDNS, one particular DNS filtering solution, on several kinds of devices.
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How to change DNS Servers in WindowsUpdated July 2024. CIPA requires libraries to unblock computers for adults if there is a research need. This article explains how to change the DNS settings in Windows 7. If you are using DNS filtering on your ROUTER, you'll need to temporality change DNS settings there instead.
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How to Change DNS Servers on Most Popular Routers (Lifewire)Updated June 2023. If you use a DNS filtering service through your router, you are filtering the entire library. If you need to unblock a site for an adult patron as required by CIPA, you'll need to use this "change DNS server" procedure.
Specific DNS filter suggestions from Idaho
We're sharing suggestions for DNS filters made by Dylan Baker of the Idaho Commission for Libraries because they seem useful to us. You might find the rest of his filtering guide useful as well. We're not afraid of second opinions.
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OpenDNS Family Shield & OpenDNS Home (Free as of Feb 2018)DOES NOT WORK WITH HUGHESNET OpenDNS Family Shield does not require an account and is pre-configured to block adult content. OpenDNS Home requires a free account but you can configure which categories are blocked (including blocking or unblocking specific websites).
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How can I tell if my ISP Allows Third-Party DNS Providers? (Open DNS)Verification from OpenDNS that its product does not work over most satellite connections.
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DNS Filter (Starting at $60/year as of Feb 2018)This service can be as low as $60/year (but could be more if you exceed 1 million DNS requests in a month). A DNS request is made whenever the computer looks up a web address. A single web page can generate multiple DNS requests.
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SafeDNS PricingMay not work with HughesNet. Contact the company for information. Pricing page for Education and Nonprofits.
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WebTitan Cloud ($405 year/25 devices as of Feb 2018)Known to work with Viasat. As of 7/2/2019 could not determine whether it worked with HughesNet.
Computer Based Filtering Programs
If you are only looking to filter a few computers in your home or library, a computer based web filtering program may be for you. Here are a few examples along with a buying guide.
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Microsoft Family SafetyFree product available to users of Windows 7, 8 and 10.
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Qustodio Parental ControlFiltering and child monitoring system.
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ContentWatch Net NannyWeb filtering and child monitoring system.
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Best Parental Control Software for 20 (PC Magazine)List of reviews of family web and monitoring software from PC magazine.
Router/Hardware Filtering
If you are looking to provide filtering at the level of your home / small office/library network, you may want to use a hardware solution. These pieces of hardware often function as WIFI hot spots in addition to providing web filter services. The following products are examples of this type of technology.
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Cisco Meraki MX64WIntegrated router and wifi hotspot with content filtering. Intended for offices and schools. Supports up to 50 users.
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iPrism from EdgewaveHardware based filtering available for purchase or lease.
CIPA Filtering Reviews and Lists from other Libraries
The links provided here represent filtering research done by libraries and library groups around the country. They are not recommendations, but do provide some insight into various products.
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CIPA Filtering for E-Rate Compliance: Product Options for Small Public LibrariesFrom CLiC (the Colorado Library Consortium) This list was prepared in October 2021.
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Internet Use Compliance & FilteringFrom the Idaho Commission for Libraries. There's a lot of information here. Check out the specific product reviews under Content Filtering.