FAQ
On this page, you can find the answers to many frequently asked questions. If you still can’t find the information you need, please refer to the support desk contact page.
What can I use URLfilterDB for?
What do I need to use URLfilterDB?
Is Linux supported?
Is ICAP supported?
How does URLfilterDB work?
What is ufdbGuard?
What is Squid?
Can I use URLfilterDB without ufdbGuard?
Can I use ufdbGuard without URLfilterDB?
What web proxies can use URLfilterDB?
What web content can be blocked?
When is a site included in a blocked category?
What adult content can be blocked by URLfilterDB?
Can I overrule categories?
Can I suggest a URL be added to or removed from the database ?
What is the difference between a URL filter and a content filter?
Why is the HTTPS protocol a security risk?
How can I configure ufdbGuard?
I want to install ufdbGuard, but compiling the ufdbGuard code results in errors
How can I test URLfilterDB before buying?
How much does a subscription to URLfilterDB cost?
How can I make payments for a URLfilterDB subscription?
URLfilterDB is a URL database that can be used by web proxy servers to block access to unwanted web content.
Back to top
You need the following hardware and software to use URLfilterDB:
Both the popular Squid web proxy and our ufdbGuard internet filter software are free!
Back to top
Yes. ufdbGuard is developed and tested on Linux 2.6.18.
Back to top
Release 2.0 will support the ICAP protocol, and hence all web proxies that use the ICAP protocol to filter URLs.
Back to top
In most companies, web browsers like Internet Explorer use a web proxy to visit the Internet. The web proxy can be extended with an Internet filter to block the content of certain web pages. The ufdbGuard Internet filtering software uses the URLfilterDB database to decide which web content is filtered. For more information, we refer to the "How it works" page on this site.
Back to top
ufdbGuard is the fastest internet filter that can be used with Squid. ufdbGuard is free and can be downloaded freely.
Back to top
Squid is a popular and free web proxy. A web proxy sits in between a web browser like Internet explorer and the Internet. Squid and ufdbGuard integrate seamlessly.
Back to top
No. The URL database comes in a format suitable for ufdbGuard only.
Back to top
Yes. ufdbGuard comes with a program to generate a .ufdb file from a plain text file or URL blacklist.
Back to top
At this moment, Squid is the only proxy server that ufdbGuard supports.
Back to top
The URL database contains a set of website categories (also known as “blacklists”). The administrator can choose what website categories should be blocked for access, and what website categories the users are allowed to visit.
URLfilterDB has the following categories :
A site is included when it contains one or more items that fit into a category. To prevent blocking too much, the database is built with a policy to include only subdomains of sites whenever possible. For example, if site1.com has a separate adult section in adult.site1.com, only this subdomain is included in the adult category. This means that www.site1.com is not in the adult category. On the other hand, if www.site2.com has a mix of adult and non-adult material that is not clearly divided into subdomains or subdirectories inside a domain, the whole domain is included in the adult category.
Back to top
The adult category includes sites that contain hardcore and softcore porn, nudity, erotic stories, erotic art, fetishes, escorts, adult portals, lingerie and sites where one must be over 18 to enter. Any "non-adult" site that has an explicit adult advertisement is also included in the adult category!
Back to top
You can block a category as a whole, while still allowing access to one particular website in that category. Just include this website in the exception category "always allow"; this prevents blocking.
If you want to block access to a single website that is not in any category (e.g. www.fbi.gov), include this site in the category "always deny".
Both categories are maintained by the proxy administrator, and never by URLfilterDB!
Back to top
You can suggest any URL for inclusion or removal of the blacklist using our website.
Back to top
A URL filter uses a URL database with verified domains to block domains. A content filter guesses the nature of each page of each website "on the fly", by scanning the web pages for words like "sex".
A URL filter has several advantages over a content filter. For instance, a URL filter can block HTTPS traffic, while a content filter cannot because HTTPS is encrypted. Moreover, the risk of an incorrect classification is significantly higher with content filters. Also, CPU requirements for content filters are generally higher than for URL filtering solutions.
Back to top
HTTPS encrypts all data that is sent between a client and a web server. This is useful for prohibiting eavesdropping on the data while it is transported over the Internet. But it also enables setting up so-called “proxy tunnels” between a PC on a protected network and any system on the Internet. Using a proxy tunnel, any system on the Internet can set up an unauthorized connection to a system on the protected network. ufdbGuard offers the unique feature of dynamically detecting and blocking proxy tunnels. A more detailed explanation is given in Why HTTPS is a security threat.
Back to top
ufdbGuard is extremely easy to configure. Once you have defined the blocking policy (e.g. which categories of sites to block), just enter this policy in the ufdbGuard configuration and you are ready to use it!
Back to top
If you get errors during the compilation of the ufdbGuard sources, the most likely cause is that the OpenSSL or Bzlib header files cannot be found. In this case, install the packages libssl-devel and libbz2-devel from the Linux installation media.
Back to top
On this website you can register for a 60-day trial version of URLfilterDB to test it against URL filters and content filters. We are confident that you will find that URLfilterDB’s speed and accuracy of blocking much superior to its competitors.
Back to top
Use the quote request form to ask for a subscription quote for your organization. Alternatively, use the ROI calculator to see how little time your ROI on URLfilterDB will be!
Back to top
We accept payments by international money transfer to our bank account in the Netherlands. The invoice contains all details to make a transfer. Customers in Euro countries will always be billed in Euro. Other customers may choose to be billed in EUR or USD.
Back to top
What can I use URLfilterDB for?
What do I need to use URLfilterDB?
Is Linux supported?
Is ICAP supported?
How does URLfilterDB work?
What is ufdbGuard?
What is Squid?
Can I use URLfilterDB without ufdbGuard?
Can I use ufdbGuard without URLfilterDB?
What web proxies can use URLfilterDB?
What web content can be blocked?
When is a site included in a blocked category?
What adult content can be blocked by URLfilterDB?
Can I overrule categories?
Can I suggest a URL be added to or removed from the database ?
What is the difference between a URL filter and a content filter?
Why is the HTTPS protocol a security risk?
How can I configure ufdbGuard?
I want to install ufdbGuard, but compiling the ufdbGuard code results in errors
How can I test URLfilterDB before buying?
How much does a subscription to URLfilterDB cost?
How can I make payments for a URLfilterDB subscription?
What can I use URLfilterDB for?
URLfilterDB is a URL database that can be used by web proxy servers to block access to unwanted web content.
Back to top
What do I need to use URLfilterDB?
You need the following hardware and software to use URLfilterDB:
| Hardware: | The hardware requirements depend on the number of users. |
| Memory: | 80 MB |
| Free disk space: | 20 MB |
| CPU | any CPU that runs Linux, FreeBSD, NetBSD or Solaris |
| CPU number and class: | |
| < 100 users: | 1 CPU, class: Pentium 3 |
| 100 – 750 users: | 1 CPU, class: Pentium 4, 2.8 GHz or better |
| 750 – 2500 users: | 2 CPUs, class: Pentium 4 |
| > 2500 users: | 2 CPUs, class: Intel Core 2 Duo |
| Software: | |
| Operating system: | Linux, FreeBSD, or Solaris |
| Web server software: | Apache |
| Web proxy: | Squid |
| Internet filter software: | ufdbGuard |
Back to top
Is Linux supported?
Yes. ufdbGuard is developed and tested on Linux 2.6.18.
Back to top
Is ICAP supported?
Release 2.0 will support the ICAP protocol, and hence all web proxies that use the ICAP protocol to filter URLs.
Back to top
How does URLfilterDB work?
In most companies, web browsers like Internet Explorer use a web proxy to visit the Internet. The web proxy can be extended with an Internet filter to block the content of certain web pages. The ufdbGuard Internet filtering software uses the URLfilterDB database to decide which web content is filtered. For more information, we refer to the "How it works" page on this site.
Back to top
What is ufdbGuard?
ufdbGuard is the fastest internet filter that can be used with Squid. ufdbGuard is free and can be downloaded freely.
Back to top
What is Squid?
Squid is a popular and free web proxy. A web proxy sits in between a web browser like Internet explorer and the Internet. Squid and ufdbGuard integrate seamlessly.
Back to top
Can I use URLfilterDB without ufdbGuard?
No. The URL database comes in a format suitable for ufdbGuard only.
Back to top
Can I use ufdbGuard without URLfilterDB?
Yes. ufdbGuard comes with a program to generate a .ufdb file from a plain text file or URL blacklist.
Back to top
What web proxies can use URLfilterDB?
At this moment, Squid is the only proxy server that ufdbGuard supports.
Back to top
What web content can be blocked?
The URL database contains a set of website categories (also known as “blacklists”). The administrator can choose what website categories should be blocked for access, and what website categories the users are allowed to visit.
URLfilterDB has the following categories :
- Adult & sexually explicit
- Advertisements
- Audio & video
- Chat
- Dating & Personals
- Drugs
- Entertainment
- External Applications
- Finance & Investment
- Forums
- Gambling
- Games
- Hacking & Warez
- Job Search & Career Development
- News
- Peer-to-peer
- Personal weblogs & private home pages
- Shops
- Sports
- Browser toolbars
- Travel
- Violence/Offensive & Hate
- Web Proxies & Anonymizers
- Web-based email
When is a site included in a blocked category?
A site is included when it contains one or more items that fit into a category. To prevent blocking too much, the database is built with a policy to include only subdomains of sites whenever possible. For example, if site1.com has a separate adult section in adult.site1.com, only this subdomain is included in the adult category. This means that www.site1.com is not in the adult category. On the other hand, if www.site2.com has a mix of adult and non-adult material that is not clearly divided into subdomains or subdirectories inside a domain, the whole domain is included in the adult category.
Back to top
What adult content can be blocked by URLfilterDB?
The adult category includes sites that contain hardcore and softcore porn, nudity, erotic stories, erotic art, fetishes, escorts, adult portals, lingerie and sites where one must be over 18 to enter. Any "non-adult" site that has an explicit adult advertisement is also included in the adult category!
Back to top
Can I overrule categories?
You can block a category as a whole, while still allowing access to one particular website in that category. Just include this website in the exception category "always allow"; this prevents blocking.
If you want to block access to a single website that is not in any category (e.g. www.fbi.gov), include this site in the category "always deny".
Both categories are maintained by the proxy administrator, and never by URLfilterDB!
Back to top
Can I suggest a URL be added to or removed from the database?
You can suggest any URL for inclusion or removal of the blacklist using our website.
Back to top
What is the difference between a URL filter and a content filter?
A URL filter uses a URL database with verified domains to block domains. A content filter guesses the nature of each page of each website "on the fly", by scanning the web pages for words like "sex".
A URL filter has several advantages over a content filter. For instance, a URL filter can block HTTPS traffic, while a content filter cannot because HTTPS is encrypted. Moreover, the risk of an incorrect classification is significantly higher with content filters. Also, CPU requirements for content filters are generally higher than for URL filtering solutions.
Back to top
Why is the HTTPS protocol a security risk?
HTTPS encrypts all data that is sent between a client and a web server. This is useful for prohibiting eavesdropping on the data while it is transported over the Internet. But it also enables setting up so-called “proxy tunnels” between a PC on a protected network and any system on the Internet. Using a proxy tunnel, any system on the Internet can set up an unauthorized connection to a system on the protected network. ufdbGuard offers the unique feature of dynamically detecting and blocking proxy tunnels. A more detailed explanation is given in Why HTTPS is a security threat.
Back to top
How can I configure ufdbGuard?
ufdbGuard is extremely easy to configure. Once you have defined the blocking policy (e.g. which categories of sites to block), just enter this policy in the ufdbGuard configuration and you are ready to use it!
Back to top
I want to install ufdbGuard, but compiling the ufdbGuard code results in errors
If you get errors during the compilation of the ufdbGuard sources, the most likely cause is that the OpenSSL or Bzlib header files cannot be found. In this case, install the packages libssl-devel and libbz2-devel from the Linux installation media.
Back to top
How can I test URLfilterDB before buying?
On this website you can register for a 60-day trial version of URLfilterDB to test it against URL filters and content filters. We are confident that you will find that URLfilterDB’s speed and accuracy of blocking much superior to its competitors.
Back to top
How much does a subscription to URLfilterDB cost?
Use the quote request form to ask for a subscription quote for your organization. Alternatively, use the ROI calculator to see how little time your ROI on URLfilterDB will be!
Back to top
How can I make payments for a URLfilterDB subscription?
We accept payments by international money transfer to our bank account in the Netherlands. The invoice contains all details to make a transfer. Customers in Euro countries will always be billed in Euro. Other customers may choose to be billed in EUR or USD.
Back to top