Network Configuration

Network configuration is the process of setting up and managing network interfaces on Linux systems to enable communication with other devices and networks.

List Network Interfaces

# List network interfaces - ifconfig
ifconfig
 
# List network interfaces - ip
ip addr

Setup Network

# Activate network interface - ifconfig
sudo ifconfig eth0 up
# OR using - ip
sudo ip link set eth0 up
 
# Assign IP 
sudo ifconfig eth0 192.168.1.10
 
# Assign Netmask
sudo ifconfig eth0 netmask 255.255.255.0
 
# Assign Gateway
sudo route add default gw 192.168.1.1 eth0
 
# Restart Network
sudo systemctl restart networking

Set DNS

# Editing file
sudo vim /etc/resolv.conf
 
# Google DNS
nameserver 8.8.8.8
nameserver 8.8.4.4

Persist across reboots

# Editing file
sudo vim /etc/network/interfaces
 
# Add configuration
auto eth0
iface eth0 inet static
  address 192.168.1.10
  netmask 255.255.255.0
  gateway 192.168.1.1
  dns-nameservers 8.8.8.8 8.8.4.4

List Listening Ports

# Show all listening ports - netstat
netstat -tuln
 
# Show all listening ports - ss
ss -tuln
 
# Show listening ports with process information
sudo netstat -tulnp
 
# Show specific port (e.g., 80)
sudo netstat -tulnp | grep 80