Network Configuration Basics When installing an operating system with network connectivity, it’s standard to connect it to the network for communication with other computers in your IT system.
Essential Network Concepts MAC Address The MAC (Media Access Control) address is the physical address that identifies your network adapter:
Format : 48 bits, 6 blocks of hexadecimal charactersExample : 74:e6:e2:35:6a:a1Assignment : Provided by manufacturerUniqueness : Should be unique worldwide
MAC addresses can be spoofed (changed), which can be used for malicious purposes and represents a security vulnerability.
IP Address (IPv4) A logical and hierarchical identifier for network interfaces:
Format : Four octets (0-255) separated by dotsExample : 192.168.1.100Purpose : Communication in TCP/IP networksAdministration : Configurable by administrators
Static IP Configuration Manually configured network settings:
IP Address The unique address for this device on the network
Subnet Mask Defines the network portion vs. host portion of the IP
Default Gateway Router IP for accessing other networks/internet
DNS Servers Servers that resolve domain names to IP addresses
Dynamic IP (DHCP) Automatic configuration via DHCP server:
Automatically assigns IP address
Provides subnet mask
Configures default gateway
Sets DNS servers
Manages lease time
DHCP simplifies network management, especially in environments with many devices.
Windows Network Configuration GUI Configuration Network and Sharing Center Access via Control Panel:
Open Control Panel
Search for “Control Panel” in Start menu
Network and Sharing Center
Click “Network and Sharing Center”
Change Adapter Settings
Click “Change adapter settings” on the left
Configure Adapter
Right-click adapter → Properties
Connection Status The status dialog shows:
Connectivity:
IPv4 Connectivity: Connected/No network access
IPv6 Connectivity: Status of IPv6 connection
Media State: Enabled/Disabled
Duration: Time connected
Speed: Connection speed (e.g., 1 Gbps)
Activity:
Bytes sent
Bytes received
If only bytes sent increases without bytes received, you likely have a connectivity problem.
Adapter Properties Configure IPv4 settings:
✓ Obtain an IP address automatically ✓ Obtain DNS server address automatically
Use when DHCP server is available on network.
• Use the following IP address: IP address: 192.168.1.100 Subnet mask: 255.255.255.0 Default gateway: 192.168.1.1 • Use the following DNS server addresses: Preferred DNS server: 8.8.8.8 Alternate DNS server: 8.8.4.4
Use when you need a fixed IP address.
Request DHCP, but use static IP if DHCP fails: ✓ Obtain an IP address automatically • Alternative Configuration: • Automatic private IP address OR • User configured: IP address: 192.168.1.100 Subnet mask: 255.255.255.0
Workgroups and Domains Windows computers must be part of a workgroup or domain:
Workgroup
Peer-to-peer networkNo central control Each computer has own user accounts
Typically ≤20 computers
Not password protected All computers must be on same network/subnet
Use case: Small offices, home networksDomain
Centralized management Shared database and security policy
Managed by domain controllers Administrators control all domain computers
Users can log in to any domain computer
Requires enterprise Windows versions
Use case: Business environments, enterprisesNot all Windows editions support domain joining. Windows Home editions cannot join domains.
PowerShell Network Management PowerShell provides powerful network configuration cmdlets.
Get Network Configuration Get-NetIPConfiguration Quick overview of network configuration:
# Show all adapters Get-NetIPConfiguration # Show specific adapter Get-NetIPConfiguration - InterfaceAlias "Ethernet" # Detailed information Get-NetIPConfiguration - Detailed
Get-NetIPAddress Detailed IP address information:
# All IP addresses Get-NetIPAddress # IPv4 only Get-NetIPAddress - AddressFamily IPv4 # Format as table Get-NetIPAddress | Format-Table InterfaceAlias , IPAddress # Format as list Get-NetIPAddress | Format-List InterfaceAlias , IPAddress # Filter by interface Get-NetIPAddress - InterfaceAlias "Ethernet"
Get-NetAdapter Network adapter information:
# List all adapters Get-NetAdapter # Detailed info Get-NetAdapter - Name "Ethernet" | Format-List # Show MAC address Get-NetAdapter | Select-Object Name , MacAddress # Show only connected adapters Get-NetAdapter | Where-Object { $_ .Status -eq "Up" }
Network Connectivity Testing Test-NetConnection Comprehensive connectivity testing:
# Basic ping test Test-NetConnection www.google.com # Detailed information Test-NetConnection www.google.com - InformationLevel Detailed # Trace route Test-NetConnection www.google.com - TraceRoute # Test specific port Test-NetConnection www.google.com - Port 443 # Test without ping (port only) Test-NetConnection server.local - Port 3389 - InformationLevel Quiet
In many corporate networks, PING (ICMP) is disabled for security. Use port testing instead.
Resolve-DnsName DNS resolution:
# Resolve hostname Resolve-DnsName www.google.com # Get all DNS records Resolve-DnsName www.google.com - Type ALL # Query specific record type Resolve-DnsName google.com - Type MX Resolve-DnsName google.com - Type SOA # Use specific DNS server Resolve-DnsName www.google.com - Server 1.1 . 1.1 # Format output Resolve-DnsName www.google.com | Format-List
Get-NetRoute Routing table:
# Show all routes Get-NetRoute # Filter by destination Get-NetRoute - DestinationPrefix "10.0.2*" # Show default gateway Get-NetRoute - DestinationPrefix "0.0.0.0/0" # IPv4 routes only Get-NetRoute - AddressFamily IPv4
Set Network Configuration # Set static IP New-NetIPAddress - InterfaceAlias "Ethernet" ` - IPAddress 192.168 . 1.100 ` - PrefixLength 24 ` - DefaultGateway 192.168 . 1.1 # Set DNS servers Set-DnsClientServerAddress - InterfaceAlias "Ethernet" ` - ServerAddresses ( "8.8.8.8" , "8.8.4.4" )
# Enable DHCP Set-NetIPInterface - InterfaceAlias "Ethernet" - Dhcp Enabled # Reset DNS to automatic Set-DnsClientServerAddress - InterfaceAlias "Ethernet" - ResetServerAddresses
Disable/Enable Adapter # Disable adapter Disable-NetAdapter - Name "Ethernet" - Confirm: $false # Enable adapter Enable-NetAdapter - Name "Ethernet" # Restart adapter Restart-NetAdapter - Name "Ethernet"
Network Diagnostics Script #!/usr/bin/env pwsh # Network Diagnostics Script Write-Host "=== Network Diagnostics ===" - ForegroundColor Cyan Write-Host "" # Adapter Information Write-Host "Network Adapters:" - ForegroundColor Yellow Get-NetAdapter | Where-Object { $_ .Status -eq "Up" } | Select-Object Name , Status , LinkSpeed , MacAddress | Format-Table - AutoSize # IP Configuration Write-Host "IP Configuration:" - ForegroundColor Yellow Get-NetIPAddress - AddressFamily IPv4 | Where-Object { $_ .InterfaceAlias -notlike "*Loopback*" } | Select-Object InterfaceAlias , IPAddress , PrefixLength | Format-Table - AutoSize # Default Gateway Write-Host "Default Gateway:" - ForegroundColor Yellow Get-NetRoute - DestinationPrefix "0.0.0.0/0" | Select-Object InterfaceAlias , NextHop | Format-Table - AutoSize # DNS Servers Write-Host "DNS Servers:" - ForegroundColor Yellow Get-DnsClientServerAddress - AddressFamily IPv4 | Where-Object { $_ .ServerAddresses.Count -gt 0 } | Select-Object InterfaceAlias , ServerAddresses | Format-Table - AutoSize # Connectivity Test Write-Host "Internet Connectivity:" - ForegroundColor Yellow $result = Test-NetConnection www.google.com - InformationLevel Quiet if ( $result ) { Write-Host " ✓ Internet connectivity OK" - ForegroundColor Green } else { Write-Host " ✗ No internet connectivity" - ForegroundColor Red }
Linux Network Configuration netplan (Ubuntu 18.04+) Ubuntu uses netplan for network configuration.
Configuration Files Location: /etc/netplan/*.yaml
Critical: YAML is indentation-sensitive. Use spaces, not tabs. Incorrect indentation causes errors.
Basic Configuration NetworkManager Renderer # /etc/netplan/01-netcfg.yaml network : version : 2 renderer : NetworkManager
NetworkManager handles all devices (ethernet auto-configured via DHCP).
networkd Renderer with DHCP # /etc/netplan/01-netcfg.yaml network : version : 2 renderer : networkd ethernets : enp0s3 : dhcp4 : yes
Static IP Configuration # /etc/netplan/01-netcfg.yaml network : version : 2 renderer : networkd ethernets : enp0s3 : dhcp4 : no addresses : - 192.168.100.10/24 gateway4 : 192.168.100.1 nameservers : addresses : [ 8.8.8.8 , 8.8.4.4 ]
Multiple Interfaces # /etc/netplan/01-netcfg.yaml network : version : 2 renderer : networkd ethernets : enp0s3 : dhcp4 : yes enp0s8 : dhcp4 : no addresses : - 192.168.100.10/24 gateway4 : 192.168.100.1 nameservers : addresses : [ 8.8.8.8 , 8.8.4.4 ]
netplan Commands # Generate configuration sudo netplan generate # Apply configuration sudo netplan apply # Try configuration (auto-rollback in 120s) sudo netplan try
Use netplan try for testing - it automatically reverts if you lose connection.
Linux Network Commands ip (Modern Standard) The modern replacement for ifconfig:
Show IP Addresses # All addresses ip addr # IPv4 only ip -4 addr # IPv6 only ip -6 addr # Specific interface ip addr show enp0s3 # Brief output ip -br addr
# Add IP address sudo ip address add 192.168.1.100/24 dev enp0s3 # Remove IP address sudo ip address del 192.168.1.100/24 dev enp0s3 # Flush all addresses sudo ip address flush dev enp0s3
Manage Interfaces # Show interfaces ip link # Enable interface sudo ip link set enp0s3 up # Disable interface sudo ip link set enp0s3 down # Change MAC address sudo ip link set enp0s3 address 00:11:22:33:44:55
Routing # Show routing table ip route # Add route sudo ip route add 192.168.3.0/24 dev enp0s3 # Add default gateway sudo ip route add default via 192.168.1.1 # Delete route sudo ip route del 192.168.3.0/24
ifconfig (Legacy) ifconfig is deprecated but still widely used. Prefer ip command.
# Show all interfaces ifconfig # Specific interface ifconfig eth0 # Brief summary ifconfig -s # Enable interface sudo ifconfig eth0 up # Disable interface sudo ifconfig eth0 down # Set IP address sudo ifconfig eth0 192.168.1.100 # Set netmask sudo ifconfig eth0 netmask 255.255.255.0 # Change MAC address sudo ifconfig eth0 hw ether 00:11:22:33:44:55
Network Testing ping # Ping continuously (Ctrl+C to stop) ping www.google.com # Send specific count ping -c 5 www.google.com # Interval between packets ping -i 2 www.google.com # Packet size ping -s 1000 www.google.com # Quiet mode (summary only) ping -q -c 10 www.google.com
tracepath / traceroute # Trace path to host tracepath www.google.com # Trace with packet size tracepath -l 1000 www.google.com # traceroute (may need install) sudo apt install traceroute traceroute www.google.com
DNS Management hostname # Show hostname hostname # Show FQDN hostname -f # Show domain hostname -d # Set hostname temporarily sudo hostname new-hostname # Set hostname permanently echo "new-hostname" | sudo tee /etc/hostname sudo hostname -F /etc/hostname
Changing hostname can break programs like sudo. Also update /etc/hosts with new hostname for 127.0.1.1
Network Diagnostics Script #!/bin/bash # Linux Network Diagnostics echo "=== Network Diagnostics ===" echo "" # Interface Status echo "Network Interfaces:" ip -br addr echo "" # Default Gateway echo "Default Gateway:" ip route | grep default echo "" # DNS Servers echo "DNS Servers:" cat /etc/resolv.conf | grep nameserver echo "" # Connectivity Test echo "Internet Connectivity:" if ping -c 1 8.8.8.8 & > /dev/null; then echo " ✓ IP connectivity OK" else echo " ✗ No IP connectivity" fi if ping -c 1 www.google.com & > /dev/null; then echo " ✓ DNS resolution OK" else echo " ✗ DNS resolution failed" fi
Best Practices
Document Network Settings
Keep records of static IPs, subnets, and gateways
Test After Changes
Always verify connectivity after configuration changes
Use Static IPs for Servers
Servers and infrastructure should have static IPs
Use DHCP for Clients
End-user devices benefit from DHCP automation
Monitor Network Health
Regularly check network performance and connectivity