Node Address Checkups

Since many routers use different software, we first ensure that we read the node's connection data correctly before making any substantial changes to the router.

Internet Protocol Addresses

When devices connect to a home network, the router usually assigns dynamic Internet Protocol addresses through a Dynamic Host Configuration Protocol. It's a network protocol that automates assigning IP addresses and other network configuration information to devices connected to a network. DHCP eliminates the need for manual configuration of IP addresses, making it easier to connect devices to a network and manage them efficiently.

When a device joins a network, it sends a request to the router, asking for an address and other network settings. The DHCP software on the router then assigns an available IP address from its pool to the device, along with the required network configuration. This IP address is leased to the device for a specific duration, after which the device needs to renew the lease or obtain a new IP address. However, this also means that devices can change their IP addresses over time, making it difficult to access your node through SSH consistently.

4.1.1 Resolve the Node's IP Address

The ip command is a versatile and powerful networking tool in Linux, used to manage and display information about network interfaces, IP addresses, and other network-related configurations. We can use the command to display the default route information in the routing table of a Linux system. The default gateway route is the network path the system uses to send packets to destinations, not on the local network. In simpler terms, it is the route the system takes when sending data to an IP address outside its local network.

ip route show default

The output will look like this:

default via <GATEWAY_IP_ADDRESS> dev eno1 proto dhcp src <NODE_IP_ADDRESS> metric <ROUTING_WEIGHT>

Alternatively, you can send a request to a commonly used and stable server IP, for instance, Google. You will receive a response with your source IP address that you can filter using the text-processing tool awk, used for pattern scanning and processing.

ip route get 8.8.8.8 | awk '{print $7}'

4.1.2 Resolve the Node's Hardware Address

Media Access Controll

A MAC address is a unique identifier assigned to network interfaces for communication on a physical network segment. It is also commonly referred to as a hardware or physical address. MAC addresses are used at the data link layer, enabling network devices such as switches and routers to identify and manage local network devices uniquely.

Each MAC address is a 48-bit number, usually represented in a human-readable hexadecimal format, including a specific manufacturer registration code and individual product lineup iterations by the manufacturer to ensure that each network interface produced by the company has a unique MAC address.

We can use the previous networking tool to retrieve information about the MAC addresses.

ip link show

The output will list all the network interfaces on the system. Look into the interface used to broadcast and send information to the outside world using an Ethernet connection. The entry you're looking for looks like this:

<NETWORK_INFERFACE_NAME>: <BROADCAST,MULTICAST,UP,LOWER_UP> ...
    link/ether <MAC_ADDRESS> brd <BROADCAST_ADDRESS>

Write down or remember both names so you can check them later on and identify your device for router settings.