Network Connectivity Check

A toolkit for diagnosing network connectivity issues and verifying host/service availability.

When to Use This Skill

Activate this skill when the user needs to:

• Check if a host is reachable (ping)
• Verify if a specific port is open on a host
• Perform DNS lookups to resolve domain names
• Diagnose network connectivity problems
• Test if a service is available

Available Scripts

Always run scripts with --help first to see all available options.

Script	Purpose
ping_host.py	Ping a host to check reachability
check_port.py	Check if a TCP port is open
dns_lookup.py	Perform DNS lookups

Decision Tree

Task → What do you need to check?
    │
    ├─ Is the host reachable at all?
    │   └─ Use: ping_host.py <hostname>
    │
    ├─ Is a specific service/port available?
    │   └─ Use: check_port.py <hostname> <port>
    │
    └─ Need to resolve a domain name?
        └─ Use: dns_lookup.py <domain>

Quick Examples

Check if a host is reachable:

python scripts/ping_host.py google.com
python scripts/ping_host.py 8.8.8.8 --count 5

Check if a port is open:

python scripts/check_port.py example.com 443
python scripts/check_port.py localhost 8080 --timeout 5

DNS lookup:

python scripts/dns_lookup.py example.com
python scripts/dns_lookup.py example.com --type MX

Common Use Cases

1. Verify web server is running: check_port.py myserver.com 80
2. Test SSH access: check_port.py server.local 22
3. Check database connectivity: check_port.py db.example.com 5432
4. Diagnose DNS issues: dns_lookup.py problematic-domain.com

Notes

• Scripts use Python standard library only (no external dependencies)
• Ping may require appropriate permissions on some systems
• Port checks use TCP connections (not UDP)
• DNS lookups support A, AAAA, MX, TXT, NS, and CNAME record types