NxFilter Tutorial
Tutorial Index

Why NxFilter?
You may want to know why you need NxFilter and where you can use it. We will talk about the advantages of running NxFilter in your network briefly.

Faster and lighter
When you implement network level filtering, it requires an extra process for your network. Your network traffic needs to go through somewhere in your network. It can be a bottle neck in your network and cause a latency problem. This is especially true when you use webproxy way of filtering as it needs to look into all the HTTP/HTTPS traffic in your network. Your users can download tons of documents and files through HTTP/HTTPS protocol. However, NxFilter uses lightweight DNS protocol for filtering. It only needs to deal with DNS queries in your network. There will be no latency problem with NxFilter.

Central DNS cache
NxFilter caches DNS responses from its upstream DNS server. Once it cached, it will be resolved in your local network. For example, when you use a public DNS server, your users may send sevral thousand DNS queries over the Internet to resolve 'google.com' a day. This is because each of your users keeps their own cache and they send the same query again when their cache expires.

However, when you run NxFilter in your local network, it keeps its own cache and it works as a centralized DNS cache. Your users will be answered by NxFilter cache. So the DNS traffic between your local network and a public DNS server will be reduced greatly. NxFilter will save you a lot of bandwidth and improve your network performance.

High scalability
We designed NxFilter as a high performance filtering software. We see many sites running NxFilter for filtering several thousand users. We can show how it performs by the usage reports from our test group users. These are the actual usage reports from real users.

NxFilter has been used by ISPs, DNS filtering business companies, schools and other business users for many years. Its performace has been proven in real world.

Transparent filtering
You want to filter the user traffic in your network while not wanting to let them know what you are doing. You can set your NxFilter as the DNS server for your network using DHCP and block outgoing UDP/53 on your router or firewall. By doing so, NxFilter becomes the only DNS server for your network and you get your filtering. Your users will not notice any difference.

Authentication support
You want to protect your network with a login procedure and differentiate users with userames and IP addresses on your report view. NxFilter offers IP and password based authentication by itself. In fact, NxFilter was the first DNS server supporting user authentication and we don't see any other DNS server or filter supporting as many ways of authentication as NxFilter does yet.

Active Directory integration
You may want to import users and groups from Active Directory and you want to apply different policies based on those imported users and groups. That's called Active Directory integration and we support this feature from the first version of NxFilter. Most software provide this kind of feature as a paid option but it is free for NxFilter.

Single sign-on
Your users don't want to go through any other login process after they logged into their PCs. But you still want to view NxFilter logging and report with associated usernames. What you need is a single sign-on implementation with NxFilter. Once a user logged into his/her PC, then he will appear in NxFilter logging and report with his PC login username.

We provides several ways of single sign-on with NxFilter. Some of them work with Active Directory but some of them can be implemeted without Active Directory. We also support single sign-on by 802.1x Wi-Fi authentication. And all these are free.

Multiple policies
You may want to have multiple filtering policies for your users. If it's in a school environment, you want to have one policy for staffs and a stricter policy for your students. You can create such filtering policies on NxFilter GUI and apply those policies based on users and groups.

Remote filtering
We provide remote filtering agents for Windows and macOS, Chromebook. And we aslo provide a way of filtering roaming iOS and Android devices by DNS over HTTPS. You can filter your users while they are away from your office. We offer these agents for free.

Very stable
You don't need to restart NxFilter frequently. Many of our users don't restart their NxFilter for several weeks before they need to update it. Some of our users run it for several months without restarting. Leave it running and you can spend your precious time on other things to do.