Cybersecurity Triage
Read-onlyInspect Established Network Connections
You need to list established TCP connections without changing network state.
Command
ss -tan state establishedBefore you run this
System impact: Read-only. Low when scoped to the shown target.
When not to use it: Do not treat it as a full security investigation; it is a point-in-time socket snapshot.
Expected output
A list of established TCP connections showing local and peer addresses and ports.
System impact
Read-only. Nothing changes. The command displays current established TCP sockets.
Recovery / rollback: no state is changed.
When to use it
Use when checking active client connections, suspicious network activity, or service traffic.
When not to use it
Do not treat it as a full security investigation; it is a point-in-time socket snapshot.
Watch this command run
Command transcript
This sanitized transcript shows the commands and output shape without exposing host details.
$ ss -ltnp
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
LISTEN 0 511 0.0.0.0:80 0.0.0.0:* users:(("nginx",pid=1907,fd=6))
LISTEN 0 128 localhost:5432 0.0.0.0:* users:(("postgres",pid=2011,fd=7))
LISTEN 0 64 0.0.0.0:22 0.0.0.0:* users:(("sshd",pid=801,fd=3))$ ss -tan state established
State Recv-Q Send-Q Local Address:Port Peer Address:Port
ESTAB 0 0 192.0.2.10:443 198.51.100.20:51422
ESTAB 0 0 192.0.2.10:5432 192.0.2.10:41430View commands shown
These are the commands shown in the sanitized transcript.
Commands shown
ss -ltnpss -tan state established
next steps
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Study mapping
Use this as independent command practice: read the notes, predict the output, then compare it with the example before using a real shell.
Useful for
- LPIC-1 style command-line practice
- LFCS style performance tasks
- Linux+ style troubleshooting review
Independent study support only. No affiliation, endorsement, exam dumps, or real exam questions.