Most routers and access points have a DHCP server enabled. These servers are responsible for assigning IP addresses to the different devices that connect to the network in a fully automatic way, according to pre-established values. Although DHCP servers are very useful, when an intruder connects to our network it automatically goes through it, so their activity is recorded.
A very useful way to know if someone unwanted has connected to our router is to consult this table and, if so, we can block these devices internally from the router by entering their MAC address in the blacklist so that although it changes from IP will still not connect.
This tutorial is recommended for advanced users and with some experience since it is a very complicated process with many specific concepts of networks.
When we check the list of devices connected to our router or the DHCP server registry we will see a list similar to the following one (it varies according to routers and models).
In it we can see how it shows us, among other sections, the following information:
- MAC address
- IP adress
- Name of the device (useful to identify it)
The data we will use to identify unauthorized users will be the device name and the MAC. The MAC is unique to each one, so we must check and record the MAC addresses of our teams. For example, from Windows it is enough to execute CMD and type ipconfig / all to know the MAC address corresponding to our network card.
The most advanced routers have the option of configuring a static DHCP server so that the same device is automatically associated with a network name and an address, which will help its identification and control.
We compare the MAC addresses of our devices with those that appear in the DHCP tables and, if one does not correspond, it is probably an intruder connected to our network.
If we have detected any MAC address that does not match any of the allowed devices, we can locate the MAC filtering section in our router and block the connection to that device. This way you will not be able to reconnect to our router.
In each router model the administration panels change. You can ask in the specific forums that we have in the portal for the different router models and we will help you to locate this section in particular for your model.
