Script Valley
Linux & Bash for Developers
Networking & SSH EssentialsLesson 5.1

Linux networking commands every developer needs

ip addr, ifconfig, ping, traceroute, netstat, ss, hostname, /etc/hosts, DNS lookup with dig and nslookup

Network Diagnostics From the Command Line

Network issues are a constant part of server work. These commands let you diagnose connectivity problems, check open ports, and inspect DNS — without needing a GUI.

IP Configuration and Connectivity

# Show all network interfaces and their IP addresses
ip addr show

# Older equivalent (deprecated but still common)
ifconfig

# Test connectivity to a host
ping -c 4 google.com

# Trace the route packets take
traceroute google.com

# Your system's hostname
hostname

Checking Open Ports and Connections

# List all listening ports (modern tool)
ss -tlnp

# Older equivalent
netstat -tlnp

# Check if a specific port is open
ss -tlnp | grep :8080

# Check what process is using port 80
ss -tlnp | grep :80

DNS Lookups

# Forward lookup: domain to IP
dig google.com

# Short answer only
dig +short google.com

# Reverse lookup: IP to domain
dig -x 8.8.8.8

# Check specific DNS record types
dig google.com MX
dig google.com NS

# Simpler alternative
nslookup google.com

# Add a custom hostname (for dev environments)
echo "127.0.0.1 myapp.local" | sudo tee -a /etc/hosts

Up next

SSH tutorial: connect to remote servers securely

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