Determining "Digital Footprints" in the Network
What is my IP address?
Communication between technical devices and applications is based on IP addresses. Every device and every application in a network has got its own IP address which is based on the Internet Protocol (IP) in computer networks. These are, so to speak, the traces left behind on the Internet and are also referred to as digital footprints. IP addresses make devices within the network accessible and enable a sender to send data packets to a specific recipient. If packets do not arrive, there is a fault in the network.
Determining the IP address is useful for checking whether a packet arrived at the recipient or where it was lost. There are several options for checking the connection on the Allegro Network Multimeter which are described in the following article.
The Allegro Network Multimeter is connected between the device and the server infrastructure to find the IP address of a network device. Using the three protocols MAC, DHCP and HTTP, the search is easy:
Layer 2: MAC-Modul
All network devices have got a unique MAC address. However, this is only visible in their own network and can only be reached as far as the next router (e.g. Fritzbox). Therefore, most devices use IP addresses for communication. The MAC address of a device can be found in the Allegro Network Multimeter dashboard. All active IP addresses of the device can be seen by clicking on it.
IP addresses are only assigned to individual network devices for a defined period of time. If the IP address is unknown, the process still works via layer 2. For this purpose, the MAC statistics are called up and searched for a specific device, e.g. the brand name of the device. Then it is navigated to the IP addresses again and the status of the device is retrieved.
Layer 3: DHCP-Modul
DHCP servers assign dynamic IP addresses to devices. If DHCP is not enabled or supported on a unit, a static IP address must be assigned manually. The DHCP statistics in the Allegro Network Multimeter are used to find out IP addresses that have been assigned by a DHCP server. In the shown list of all IP addresses assigned via DHCP it is quick and easy to search for a host name or the manufacturer of the unit, for example. The period of time of the address assignment can also be conveniently limited.
Layer 7: HTTP-Modul
The HTTP module also provides access to IP addresses. If, for example, the IP address of a mobile phone is to be found out, any website (e.g. allegro-packets.de) must be opened on the mobile phone and it must be navigated to the HTTP statistics. Here, the server (website) is searched for and the IP address of the web server appears. Clicking on the IP address shows the details. There it gets visible which IP addresses have been in contact with the server and at which time. There are also websites that directly display the called IP. However, only the public IP of the Internet connection is visible there - not the IP of the end device. This is possible with the Allegro Network Multimeter.
These application examples on IP addresses are summarised in the following video. Product Manager and Managing Director Klaus Degner shows here how to find out the IP address of a network device with the Allegro Network Multimeter.
DNS, with its name resolution, is an important service in many IP-based networks. Would you like to learn more about the topic? We have prepared a blog article with a video for you here.