network-info

Original source / Raw SKILL.md

---
name: network-info
description: Gather network configuration and connectivity information including interfaces, routes, and DNS
---

# Network Information Skill

Use this skill to explore network configuration and connectivity on Linux systems.

## Quick Start

Run the included script for a network overview:

```bash
./scripts/netinfo.sh
```

## Manual Commands

### 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


---

## Referenced Files

> The following files are referenced in this skill and included for context.

### scripts/netinfo.sh

```bash
#!/bin/bash
# Network Information Script
# Outputs network configuration details in a structured format

echo "=== NETWORK INFORMATION ==="
echo

echo "--- Network Interfaces ---"
if command -v ip &> /dev/null; then
    ip -br addr
else
    cat /proc/net/dev | tail -n +3 | awk '{print $1}' | tr -d ':'
fi
echo

echo "--- IP Addresses ---"
if command -v ip &> /dev/null; then
    ip addr show | grep -E 'inet |inet6 ' | awk '{print $2, $NF}'
else
    hostname -I 2>/dev/null || echo "Could not determine IP addresses"
fi
echo

echo "--- Routing Table ---"
if command -v ip &> /dev/null; then
    ip route
else
    cat /proc/net/route | head -5
fi
echo

echo "--- DNS Configuration ---"
if [ -f /etc/resolv.conf ]; then
    grep -E '^nameserver|^search|^domain' /etc/resolv.conf
else
    echo "No /etc/resolv.conf found"
fi
echo

echo "--- Listening Ports ---"
if command -v ss &> /dev/null; then
    ss -tuln | head -20
else
    cat /proc/net/tcp | head -10
fi

```