Connect each conclusion to its source

The stream is synthetic. The listener and missing-echo cards are
separate fictional evidence. Only the TCP stream is in the pcapng file.
Identify the response direction, then choose the kind of diagnostic
that would inspect a listener or send an echo request. Do not send the
drawn probe. List possible causes without declaring one proven.

Historical file-read record, 2026-10-12: TShark 4.2.2 read keep plus
newline and kept plus newline from network-observation.pcapng. This was
a read of synthetic bytes, not live traffic or a Wireshark GUI session.

Traffic stage review case. Synthetic stream plus two fictional cards.
network-observation.pcapng serializes only the TCP stream.
The echo card and the listener card are not packets in that file.

Stream
desk 192.168.50.10 port 49170, shelf 192.168.50.23 port 9090
Setup: SYN, SYN-ACK, ACK
desk to shelf: keep
shelf to desk: kept
Predict before reading the check. Check word: kept

Listener card, not ss output
State   Local address
LISTEN  192.168.50.23:9090

Echo card. Do not send the probe.
Drawn probe: ping -c 2 203.0.113.10
Drawn result: no echo reply
Hypotheses that fit: the echo was filtered, or the sender had no route.
Silence does not prove the host is powered off.

Rubric
1. The stream response word is kept.
2. A question about the listener is answered by the socket-listing command. The echo command answers a different question.
3. Name two hypotheses for the missing echo. Do not scan, and do not capture a shared network.