Linux › Module 4 › Lesson 2
ping, traceroute, netstat
Test connectivity with ping, trace paths, and inspect sockets
Opening
Is it up? Is it reachable? Who is listening?
Networks fail in boring ways—cable unplugged, firewall, wrong IP. ping and traceroute answer reachability. ss/netstat show what ports your box listens on. Basic recon starts here.
1. ping — Hello, Are You There?
Send ICMP echo requests to test connectivity: ping 8.8.8.8 ping cyberlium.com Ctrl+C to stop. No reply might mean down host, firewall blocking ICMP, or routing issue—not always "hacked."
2. traceroute — Hop by Hop
Shows the path packets take: traceroute cyberlium.com traceroute 8.8.8.8 On some systems use tracepath or mtr. Useful when ping works but a website does not—find where traffic dies.
3. ss and netstat — Open Ports
See listening services: ss -tuln — TCP/UDP listening, numeric ports netstat -tuln — classic (may need net-tools) LISTEN on 0.0.0.0:22 means SSH accepts connections on port 22 from any interface.
Defender habit
After hardening a server, run ss -tuln and confirm only expected ports are open (22, 80, 443—not random high ports).
Knowledge Check
ping is primarily used to:
Multiple choice
Knowledge Check
traceroute helps you:
Multiple choice
Knowledge Check
ss -tuln is useful for finding:
Multiple choice