Category Archives: Network management

How to detect ip conflicted devices in your network with WFilter?

IP conflict in local network can be annoying. When ip conflicts happens, it will cause connection issues. And it’s rather difficult for an IT administrator to locate the conflicted devices.

With WFilter, life is easier.

First, you can block the conflicted devices with a message. As shown in below figure, you can send a message “Your ip address conflicts with our server, please correct it ASAP”. This message will show up when browsing http sites. So the client can fix this issue by himself.


Second, you can run the “Network Health Checker” extension, which can test ip conflicts in your network. The screenshots:


Conflicted devices will be detected, with its mac address and manufacturer.

In this example, now you may talk to the person with “HuaWei” mobile to correct the conflict issue.

Extension home page: “Network Health Checker”

Wiki page: Check network health of availability, IP conflict, ARP spoof and broadcast storm

What’s the difference between Pass-by filtering and Pass-through filtering?

Filtering technologies are divided into two types: Pass-through (sever plug-in based) and Pass-by (standalone-based).


A Pass-by filter usually monitors and filters network traffic with the help of port mirroring while a Pass-through filter monitors and filters network traffic on a gateway or bridge.


The differences between Pass-by filtering and Pass-through filtering: Advantages of Pass-by filtering:


1. Pass-by filtering is easier to be deployed. You only need to setup a mirroring port in your switch without the need to change your network topology. However, since pass-through filtering needs to be installed in the gateway or bridge, usually you need to change your network topology to deploy a pass-through filtering product.


2. Pass-by filtering product, such as WFilter Enterprise, only deals with copies of network packets, without any delay of the original packets. Even a pass-by filtering product stops working, your internet connection stays alive.


However, because a Pass-through product “stops and checks” network packets, it is unavoidable to make slight delay to your internet access. And, when a pass-through filtering product stops working, you will lose your internet connection.


Disadvantages of Pass-by filtering:


1. Port mirroring is required for pass-by filtering, you can not monitor or filter your network without a manageable switch.


2. A pass-by filtering product sends RST packets to terminate TCP connections, however, UDP traffic can not be blocked by pass-by filtering. Usually, you also need to block certain UDP ports in your router for completely blocking.


3. Traffic shaping and QoS is unavailable in pass-by filtering, since it only deals with copies of network packets.

For more information about WFilter technical details, please check: WFilter Inside Technologies.