Category Archives: How to block internet

How to block internet access of guest computers in network?

Guest computers might come and leave for a network. However, unmanaged internet access of guest computers could be a nightmare for your network. Guest computers can consume most of your bandwidth with p2p downloading, and download copyrighted materials or virus which might be harmful.

This tutorial will guide you to setup a default internet blocking policy for guest computers with WFilter 3.3 version.

1. Set a different ip address range for guest computers.

If guest computers share a same ip address range with your existing computers, you won’t be able to recognize them. For management purpose, the guest computers shall be in a different ip address range. For example:

1. Allocate all you existing computers with static ip addresses from “192.168.1.0″ to “192.168.1.200″.

2. In your wireless AP, set the DHCP range from “192.168.1.200″ to “192.168.1.250″.

Now every guest computers(mostly laptops) will get an ip address in range “192.168.1.200 – 192.168.1.250″. Then you can set a blocking policy for them in WFilter.

2. Setup default blocking policies for certain ip ranges.

Now you can setup a default blocking policy for ip address in range “192.168.1.200 – 192.168.1.250″. Every new computers in this ip range will be applied with this default policy.

Please notice: If you can not setup a different DHCP range for guest computers, you also can enable this “default monitoring policy” for new found computers. This feature is for WFilter to automatically configure monitoring and blocking policy when it detects a new computer.

More information, please check “WFilter Enterprise”.

Other related links:

How to
block internet downloading?

How
to monitor internet usage on company network?

Internet
monitoring software for business

How to filter
web surfing?

How
to block websites and restrict internet access?

How
to block HTTPS websites on my network?

 

How can I block tor or other similiar application?

1. What is tor ?

Tor is a system intended to enable online anonymity, composed of client software and a network of servers which can mask information about users’ locations and other factors which might identify them. Use of this system makes it more difficult to trace internet traffic to the user, including visits to Web sites, online posts, instant messages, and other communication forms. It is intended to protect users’ personal freedom, privacy, and ability to conduct confidential business, by keeping their internet activities from being monitored. The software is open-source and the network is free of charge to use.

Since client workstations can use tor to bypass internet filtering, so you may want to block tor traffic in your network.

In this tutorial, we will guide you to block tor traffic with “WFilter
Enterprise 3.3″.

2. How to block tor with Wfilter?

Because tor uses HTTP/TLS to encrypt its traffic, we need to use “HTTPS black/white list” feature of WFilter to filter HTTPS websites to block tor.

First, create a new “HTTPS White List” and add the allowed HTTPS domains in it. As in below figure:


Enable “HTTPS black/white list” in certain blocking level settings.

Finally, apply this blocking policy to certain computers.

3. Now tor will be completely blocked.


Blocking events in WFilter:

More information, please check “WFilter Enterprise”.

Other related links:

How to block
internet downloading?

How
to monitor internet usage on company network?

Internet
monitoring software for business

How to filter web
surfing?

How to block websites and restrict internet access?
How to block HTTPS websites on my network?

How to block Skype?

1. What is Skype?


Skype is software that enables you to make free video and conference calls, send instant message and share files with other Skype users. Skype uses both TCP and UDP to communicate with dynamic ports, which makes it difficult to block it. For more details about skype protocol, please check: Skype protocol.


2. How block Skype with Wfilter ?


WFilter makes it simple to block skype traffic in your network from a central server. However, because WFilter is a pass-by filtering product, it can only detect and block skype TCP traffic. So you also need to block UDP ports 1024-65534 in your router of firewall. For more information about “pass-by filtering”, please check: What is the difference between passby filtering and passthrough filtering?


(1) Add a blocking level and enable “Block Skype”



(2)Apply blocking level to computers you want to block.



(3)Now skype will not able to connect anymore


 



 



More information, please check “WFilter Enterprise”.


Other related links:

How to block internet downloading?
How to monitor internet usage on company network?
Internet monitoring software for business
How to filter web surfing?
How to block websites and restrict internet access?
How to block HTTPS websites on my network?

WFilter in comparison to other similar products.

There are a lot of products for you to manage your network: firewall, content filtering, web filtering proxy… Some users might get confused to choose them.
Since more and more customers had requested a comparison of WFilter to other similar products, I wrote this guide to list some important differences.

WFilter is a passby internet monitoring and filtering software program. It monitors network traffic from a mirroring port in your switch. When a TCP connection needs to be blocked, WFilter will send 1-2 RST packets to reset this connection. This is called “Passby Filtering”. More technical details of WFilter can be found at: WFilter Technologies

WFilter VS firewall program/appliance

Advantages:

1. WFilter monitor and archive most internet activities, while firewalls don’t keep internet usage details.

2. WFilter parses protocols at the application layer, it can recognize 100+ common protocols according to their signatures and behaviors. Most firewall program/application filters packets based on ports or ip addresses.

3. WFilter analyse copies of internet packets from a mirroring port of your switch. It is easy to be deployed, without any delay of your network. However, a firewall program/appliance needs to be deployed at the edge of your network. And since each packet goes through the firewall program/appliance, there will be a slight delay.

4. If the WFilter server goes down, the Internet connection stays alive. If the firewall program/appliance hangs, you will not be able to access internet.

5. WFilter is a content filtering product. It is designed to monitor and filter internet usage of employees to raise your productivity. However, a firewall program/appliance is designed to filter network packets and protect your network.

Disadvantages:

1. WFilter can not block UDP packets. So you also need to block UDP ports in your router/firewall.

2. WFilter consumes more memory and disk space of your computer. If you archive all internet activity, it might consume 2-3M disk space for each monitored computer every day.

WFilter VS open source web filtering projects

Some open source projects, like “SQUID” and “dansguardian”, also provide web filtering solutions. Below I list some major differences:

1. Most open source projects work as a proxy server. It requires you to change your internet access to proxy mode.

2. Most open source projects are web filtering only. Blocking of p2p traffic, internet monitoring/archieving are not supported.

3. Lack of statistics and reports for open source projects.

4. Lack of support for open source projects. Since protocols are changing, live update/support is required to keep your pattern database up to date, while most open source projects don’t have such support. In IMFirewall protocol lab, to keep our pattern database up to date, we have a system to monitor most common internet products/protocols, so when a new version of certain product is released, our team will work on it immediately.

Try “WFilter Enterprise” by yourself: http://www.imfirewall.us/WFilter.htm

How to block TeamViewer on my network using WFilter?

TeamViewer is a computer software package for remote control, desktop sharing, and file transfer between computers. The software operates with Microsoft Windows, Mac OS X, iOS, and Linux. It is possible to access a machine running TeamViewer with a web browser.

With TeamViewer, it will be very convenient for employees to access computers in their homes, transfer files to remote computers. So for security purpose, sometimes you may want to block TeamViewer on your network.

This tutorial will guide you to block TeamViewer with “WFilter Enterprise 3.3″.

Because blocking of Teamviewer is not supported by default in WFilter, in this example, we uses “Customize Protocols” feature of WFilter to define TeamViewer protocol.

First, Add “TeamViewer” Protocol.


.
TeamViewer has two patterns:
1. “teamviewer01″:
  Type — “HTTP SEND”
  Format — “X-IM-URL”
  Content — “s=.*\&(p|id)=.*\&client=.*”

2. “teamviewer02″:
  Type — “TCP ALL”
  Format — “0″
  Content — “^\x17\x24[\x00-\xff]{2}[\x00-\x02]“


Second, Enable blocking of teamViewer in certain blocking levels.



And apply this blocking policy to certain computers.



Now, TeamViewer will be blocked.

WFilter blocking events:



Failure connection of teamViewer.



More information, please check “WFilter Enterprise”.
Other related links:
How to block internet downloading?
How to monitor internet usage on company network?
Internet monitoring software for business
How to filter web surfing?
How to block websites and restrict internet access?

How to block BBC online video with WFilter?

One customer reported that BBC online video can not be blocked by WFilter, even “Block Online HTTP Video and Downloading of Video Files” is checked in certain blocking levels.
So we did some research and found, other than HTTP protocol, the BBC websites also use the RTMP (Real Time Messaging Protocol) to play online video.
Because blocking of RTMP is not supported by default in WFilter(will be added soon), this tutorial will guide you to block BBC online video by the “Customize Protocols” feature of WFilter.

First, Add a new protocol named “RTMP”.


1. Protocol Settings:
Protocol Name: RTMP
Protocol Desc: Real Time Messaging
Protocol Type: Streaming

2. Pattern1
Name: RTMP_HTTP
Desc: RTMP_HTTP
Type: HTTP SEND
Offset: 0
Format: User-Agent
Content: Shockwave\sFlash

3. Pattern2
Name: RTMP
Desc: RTMP
Type: TCP_SEND
Offset: 0
Begin Byte: 03
Format: 0
Content: \x03[\x00-\xff]{4}\x80\x00

Second, Enable blocking of RTMP in certain blocking levels.

Now, BBC videos will be successfully blocked.

Related Topic: How to block bbc iplayer?

How to restrict employees internet access on your network?

Internet can be a benefit to business when used properly, but internet
is often abused by employees and poses significant liability and
security risks. Used
improperly, the Internet can subject every organization to harassment claims,
countless hours of lost productivity and innumerable security leaks and
vulnerabilities.

Several important risks caused by improper internet usage:
1. Virus Infection
2. Lost Productivity
3. Legal liability
4. Bandwidth consumer

So it is necessary for you to restrict employees internet access on your network.

To achieve this goal,  first you need an internet access policy, which should be able to:

1. Clarify what constitutes acceptable use of Internet services.
2. Ensure employees understand who to contact with questions regarding acceptable use.
3. Ensure employees understand the penalties that arise from Internet misuse.
4. Help lessen an organization’s spyware and virus infestation rates.
5. Provide human resources with signed documentation from each employee stating a pledge not to improperly use Internet services.
6. Help mitigate productivity losses.
7. Decrease dependence upon technology solutions used to enforce employee behavior.
8. Reduce the organization’s liability resulting from harassment claims, copyright violations originating onsite and other illegal acts.

You also need an internet filtering product to assure your internet policy. Let’s take “WFilter Enterprise” as an example, it enables you to monitor and filter internet access for all computers from a mirroring port of your switch. You only need to install WFilter in one computer to monitor the whole network.

Key Features:

  • Keep a detailed record of each web surfing and web posting.
  • Record all incoming and outgoing email content and attachment.
  • Monitor and archive instance messengers chat contents and activities.
  • Monitor and archive files transferred by web, ftp and IM tools.
  • Implement a policy to filter internet access during working hours.
  • Websites, messengers and p2p file downloading can be blocked to save bandwidth and raise productivity.
  • You only need to install WFilter in ONE computer to manage your whole network.

http://www.imfirewall.us

How to block google talk in gmail with WFilter?

Though official Google Talk protocol is XMPP, it is more
complicated and flexible than XMPP. Google Talk (GTalk) provides several ways for you to access your gtalk account, including:

  • 1). Official  “Google Talk” client.
  • 2). Gmail chat in google mail account.
  • 3). Google Talk Gadget — a web version of Gtalk.

This makes it complicated for you to block usage of google talk on company network. This tutorial will guide you to block google talk, gmail chat and google talk gadget using WFilter.

WFilter identifies Google talk connections by signature matching. Blocking google talk is simple in WFilter.

The below examples demonstrates blocking of google talk and gmail chat.

1. Blocking of jabber, gmail chat and gadget

Set a blocking policy in WFilter to block jabber and google talk:

2. Blocked Google talk:


3. Blocked gadget


4. Blocked gmail chat

How to block file uploading to internet on company networks?

For security purpose, you might want to block employees file uploading to internet on your network. However, since there are so many tools can be used for uploading, it is extremely difficult to block them all.

Files can be uploaded in various ways:
1. Upload to certain websites, eg: webmail, file sharing websites…
2. Using msn/yahoo/icq messengers to send files.
3. Email attachments.
4. FTP
5. Other third party tools.

WFilter provide a simply solution to block file uploading on company networks. Using WFilter, you can block file uploading and file transfers of all computers from ONE computer.

This tutorial will guide you to block file uploading using WFilter.

First, block file uploading to websites.


Please notice “block uploading files via web pages” only works on HTTP websites. To control HTTPs websites, you can use “HTTPS black/white list” in “Others” of WFilter.

Second, block email attachments.


Third, block FTP and file transfer via messengers.


Last, block unknown protocols.

Blocking unknown protocols blocks file uploading using other unknown third party programs.


More information, please check “WFilter Enterprise”.
Other related links:
How to block internet downloading?
How to monitor internet usage on company network?
Internet monitoring software for business
How to filter web surfing?
How to block websites and restrict internet access?
How to Block Bittorrent and bitcomet?
How to block msn file transfer?
How to block certain websites to save your productivity?
How to block AIM using WFilter?

How to block google talk and gmail chat on company network?

Google Talk (GTalk) is a free Windows and web-based application for instant messaging and voice over internet protocol (VOIP), offered by Google Inc. You may use “Google Talk” to send instant messages, transfer files, make PC-to-PC calls and audio conferencing.

However, sometimes you may want to block usage of google talk on company network. This tutorial will guide you to block google talk using WFilter.

Though instant messaging between the Google Talk servers and its clients uses an open protocol XMPP, it is more complicated and flexible than XMPP.
Google talk uses several ports to connect to its server:

1). Using Jabber standard tcp port 5222.
2). Using TLS port 443.
3). Using web chatting on port 80 in gmail.

So you can not block Google talk by simply blocking Jabber standard port. WFilter makes it simple to block google talk. Google talk connections can be identified and blocked by signature matching.

The below examples demonstrates blocking of google talk.

1. Blocking of Google talk and gmail chat

Set a blocking policy in WFilter to block jabber and google talk:

Blocked Google talk:

2. Block file transfer of Google talk

You also can block file transfer of Google Talk in WFilter. This will block file transfer of google talk without blocking of normal google talk text messaging.

More information, please check “WFilter Enterprise”.
Other related links:
How to block internet downloading?
How to monitor internet usage on company network?
Internet monitoring software for business
How to filter web surfing?
How to block websites and restrict internet access?
How to Block Bittorrent and bitcomet?
How to block msn file transfer?
How to block certain websites to save your productivity?
How to block AIM using WFilter?