Author Archives: WFilter

WFilter WebVPN introduction and example

WebVPN allows a user to securely access resources on the corporate LAN from anywhere with a web browser. The client user must authenticates itself before access any resources.
Compare to other VPN services, WebVPN is easier to deploy and operate. Client users don’t need to install any software clients or settings.

In this guide, I will demonstrate you how to setup and use the WebVPN service of WFilter NG firewall.

First, you need a domain.

Domain shall be mapped to your network public ip address.

Enable the “WebVPN” service, setup domain name, port and authentication.

Add local web services.

Edit the webvpn portal.

Setup “port forwarding” to forward internet access to webvpn port.

Now, let’s check how WebVPN works from client side.

You need to authenticate yourself.

After successful authentication, the web portal shows up. Then you can click a link to visit internal web service.

How to whitelist websites in WFilter?

In WFilter NG firewall, whitelist a website is very simple. You simply need to put the domain in the allowed list of “web filter”. Screenshot as below:

However, real world webpages can be complicated. For example, webpage A also includes resources from website B. So webpage A can not display correctly unless website B is also whitelisted.

To find out the domains of website B, you have to solutions:

Solution one: check the blocking events in WFilter.

In “realtime bandwidth”, click the bandwidth number of the testing client. You will be able to check the “blocking events”. All recent blocked domains/IP will be listed. So, you can find out the external domains.

Solution two: check network activites in browser.

By press F12, you will be able to check network activites of your browser. So you know which resources/urls are not loaded.

With the above two solutions, you can find the extra domains to be whitelisted. You need to add these domains to the allowed list in web filter.

How to block uploading to https webpages?

In “how to block file uploading to internet in business networks“, I’ve introduced a windows software solution using “wfilter internet content filter” program. However, this solution does not work for https webpages. In this guide, I will introduce a new feature in WFilter NG firewall, which can block all uploads including https webpages.

In “App Control” of WFilter NG firewall, you can enable “block sessions when outgoing traffic exceeds N” option. This option will check the outgoing traffic of every connection. If outgoing traffic exceeds the choosen limit, this connection will be terminated.

Now let’s check the blocking effects.

“Email attachments” will be blocked(https).

“Blog and forum attachments” will also be blocked(http).

And you also be able to see the “uploading detected” blocking events in WFilter.

Please also note: this option blocks uploading according to outgoing traffic checking, so there will be false positives. For example, a video conference will also be blocked due to high outgoing traffic. In this case, you may add “Exceptions” to avoid over-blocking.

How to monitor network activities on your openwrt/lede WiFi router?

WFilter internet content filter software can monitor internet activities of network clients. However, the deployment requires you to setup port mirroring in your switch to mirror all internet packets to WFilter for monitoring. Below is a typical network diagram of WFilter deployment:

In many soho networks, there is no manageable switch for port mirroring. In this guide, I will demonstrate a light solution to setup port mirroring directly in your WiFi router. First, you need to get an openwrt/lede WiFi router(or you can reflash your router with openwrt/lede firmware)
Let’s check the network topology first:

The main router is a WiFi router(192.168.1.1) running openwrt system. A PC with WFilter installed is connected to this WiFi router using a cable, with IP address 192.168.1.2. Other network clients are all wireless. Packet port-mirroring is also installed in this openwrt system.

You need to enable port-mirroring service in openwrt to mirror network packets to the WFilter pc, syntax:

Settings:

1) target: the target pc ip address, or interface

2) source_ports: wlan0(the wireless adapter)

Then you shall be able to monitor all clients internet activities in WFilter UI. Screenshots:

You also can setup internet filtering policies to block websites or applications.

Software to monitor and track emails of network clients.

Emails sent or received through a company email account are generally not considered private. As an internet filtering and monitoring software program, WFilter is able to monitor and archieve network emails.

This guide will demonstrate you how to track and monitor emails of network clients with WFilter NG firewall. Please note that we’re talking about emails sent/received via email clients, not web-based emails. Email clients in computer/laptop/smart phones can all be monitored.

1. Plain text pop3/smtp/imap can be directly recorded.

When WFilter NG firewall is deployed, plain text text pop3/smtp/imap can be directly archieved.

2. “SSL Inspection” shall be enabled to monitor SSL protected emails.

If email connections are “SSL enabled”, you need to enable “SSL Inspection” to decode and parse SSL protected emails.

SSL protected emails can also be recorded.

Web filtering software solution for network.

To filter websites of local network clients, you can have several options.

First check the features of your internet router/gateway. If you have a powerful router/gateway, you can directly do monitoring/filtering in the router itself.
You also can try pass-by filtering software solutions. For example, WFilter internet content filter, by setting up a mirroring port in your switch, you can get powerful internet monitoring and filtering with the WFilter program.

Network diagram:

WFilter is a windows software program. You can install it in any windows pc, when the wfilter pc is connected to the mirroring port of your switch, you will be able to monitor/filter all network clients.

In WFilter, you can setup internet filtering(application control) and website filtering policies.

You also can block websites by categories, for examples, porn/malicius/streaming sites can all be blocked by one click.

How to unblock an app or website in WFilter?

Sometimes when blocking policies are deployed with WFilter, some applications or website might be blocked unexpectedly.

In this guide, I will demonstrator you how to check the blocking reason and add exceptions.

First, check the blocking events

In “Realtime bandwidth”, click bandwidth number of the blocked clients.

You will be able to see the “blocking events”. In “blocking events”, you will get the “blocking reason”, “protocol” and “content”. The “content” shows the domain/IP address being blocked.

Second, add sites to “exception” list

To whitelist the blocked sites/ip addresses, you can add an “exception” policy. Excepted targets won’t be blocked by any other policies.

Third, test and check

Now make some tests to make sure your sites not blocked. If still blocked, you need to redo 1-2 steps until success.

How to block tor browser in network?

Some users might use tor browser to bypass the control of company firewall, and makes your firewall useless. In this topic, I will guide you to block tor browser traffic in your network with WFilter ICF(internet content filter).

1. Define tor browser protocol

New a “torbrowser” protocol in “System Settings”->”Protocols”.

New pattern, choose “TLS2″ type, “Offset” as “0″, “Pattype” as “Regular Expression”. Patterns: “\x01\x02\x02\x02\x03\x00\x0F\x00\x01\x01$”.

Save settings and apply the changes.

2. Deploy a tor blocking policy

Add a blocking policy, set “Torbrowser” to “Deny” in “applications”.

Apply this policy to certain client devices.

3. Test and checking

After above steps, the tor browser shall not be able to establish a tor network connection.

In “live connections” of WFilter, you can see “tor browser” being blocked.

SMS Wi-Fi authentication solutions

In previous posts, we’ve discussed various method of Wi-Fi authentication, including “username & password authentication”, “wechat Wi-Fi” and “facebook Wi-Fi”…

SMS Wi-Fi requires clients to input a mobile phone number to receive an access code before visiting internet. So the internet provider can record clients phone numbers for marketing or security purpose.

In this post, I will guide you to enable SMS Wi-Fi authentication in WFilter NG firewall.

First, you need to setup a SMS service.

WFilter send SMS messages via web API, so you need to setup a SMS web service at first. The SMS web service can be in locale or internet.

In this practice, I setup an alibaba cloud account and downloaded the php SDK. The SDK is setup in a local web service. I also modified the SDK demo to get “phone” and “code” from web POST parameters.

Second, enable SMS authentication in WFilter.

In “Web Auth”, you need to choose “SMS” auth type. The “SMS API URL” is configured as the local SDK demo URL.

When a client want to visit internet, a web portal will appear. The client needs to input a correct phone number to receive the access code.

In WFilter account login history, you will be able to see the ip address, mac address and phone number of Wi-Fi clients.

Clients internet activities will also be recorded.

More details about “web authentication” can be found at here: http://wiki.wfilterngf.com/Webauth

IP mac history is now available in WFilter NG firewall.

In the last version of WFilter NG firewall(2017.09.01), we’ve added ip mac history for all network clients. With this feature, you will be able to:

Query ip and mac address history of all network clients.
Gateway and bridge deployment are supported. You can record ip-mac activities even in bridge mode.
When “mac address detector” is enabled, you’re able to record ip-mac information in multi-subnet networks.

Below are some screenshots:

Internet content filtering solutions for business – WFilter Blog

Internet content filter and firewall solutions for business network.