Network Information Skill

Explores network configuration and connectivity on Linux systems.

Suggested Workflow

1. Run ./scripts/netinfo.sh for a structured overview of interfaces, IPs, routes, DNS, and listening ports.
2. Check ip addr for interface status and assigned addresses.
3. Verify routing with ip route and DNS with cat /etc/resolv.conf.
4. Inspect listening services with ss -tuln to identify open ports.

Commands Reference

Network Interfaces

• ip addr or ip a - Show all network interfaces and IP addresses
• ip link - Show interface status (up/down)
• cat /sys/class/net/*/address - MAC addresses

Routing

• ip route - Show routing table
• ip route get 8.8.8.8 - Show route to a specific destination

DNS Configuration

• cat /etc/resolv.conf - DNS servers
• cat /etc/hosts - Local host mappings
• systemd-resolve --status - DNS status (systemd systems)

Active Connections

• ss -tuln - Show listening TCP/UDP ports
• ss -tupn - Show established connections with process info
• cat /proc/net/tcp - Raw TCP connection data

Network Statistics

• ip -s link - Interface statistics (bytes, packets, errors)
• cat /proc/net/dev - Network device statistics

Tips

• Use ip commands (modern) over ifconfig/netstat (deprecated)
• The -n flag prevents DNS lookups for faster output
• Check ss -tuln to see what services are listening