Category: Networks

[Product Review] LC Gigabit Ethernet Port Switcher

Ethernet Port Switch

I recently purchased the LC Gigabit Ethernet Port Switcher from Aliexpress. It appears to be manufactured by Shenzhen LC Technology Co., Ltd, although the product’s web page seems incomplete. Given the electronic nature of the device (specifically for its switching functionality), the ability to switch to a different Ethernet connection using a GPIO is intriguing. This approach can maintain network or device isolation at the hardware level, enabling connectivity only under specific circumstances.

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Network Tap v2 MiTM Edition

Network Tap v2 - MiTM Edition

In my previous post I described how to utilize a Raspberry Pi and capture the traffic from a network device’s SPAN port. In this post, you will find out how to create a proper Network Tap which directly intercepts a network device’s traffic. This is actually a hardware variance of the Man in the Middle Attack (MiTM) which eliminates the requirement for network speed degradation of the Passive Taps.

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Raspberry PI 4, 400 and CM custom MAC Address

Today I read this official document (published on September of 2022) which describes how to change the MAC Address of Raspberry PI Devices. Interestingly it describes a different method for Raspberry Pi 4, 400 and CM 4 by editing the EEPROM configuration, using the following command:

sudo -E rpi-eeprom-config --edit

In the configuration file append a new line with the required MAC Address as follows:

MAC_ADDRESS=aa:bb:cc:dd:ee:ff

Save the new configuration (Use Ctrl + X to stop editing, Y to overwrite current file and ENTER to confirm). Upon saving the following message appears:

Pi4_mac_change

Finally, reboot your device in order to apply the new MAC Address. Warning If the device gets IP from a DHCP server, then most probably after the reboot it will be assigned with a new IP address.

This is a different (and simpler) technique from the one which I described in a previous post (which works for all models)

Network Watchdog

Novamostra Network Watchdog

In general a watchdog is a piece of equipment that supervises other systems and resets them in case it detects that those systems are failing, automating the process and increasing the reliability of the system. Network Watchdog is a simple watchdog for monitoring network connectivity and power cycle a device based on ICMP ping replies.

With it’s minimal power requirements, Network Watchdog can use the controlled device’s DC Power source (between 5 and 12 volts) to function, avoiding any additional power requirements. The following is an example setup:

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Manage Network Connections using Batch Scripts

Windows offer many different ways to manage your Network Connections including adapters status/configuration and network routing from the Command Line. The most frequently used are the Windows Management Instrumentation Command Line and the Netsh Command Line utility. Those commands can be used to automate Network Configuration in Batch Scripts.

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Arduino Network Tester

How many times you wanted to know if an Ethernet plug or port has internet connectivity and you had to bring your laptop or a cable from the next room to check? And how many times the only tools available were the simple Network Cable tester and your provider’s Modem or Router? For me that was a common issue and of course there was no easy, "plug and play" solution (at a reasonable price!!). Taking these into consideration I decided to give a solution by making a simple optimization to the most common Network tool. Arduino Network Tester, extends the functionality of the well-known Network Cable tester by adding DHCP, DNS and Internet connectivity tests using an Arduino Pro Mini and a W5500 Ethernet Shield with an overall cost of less than €15!
Arduino Network Tester

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