Quiz: logs from many machines

Read the output

The collector runs on a machine with address 10.0.0.5. Other machines' lines over TCP do not reach it. Why, judging by this output?

$ sudo ss -lntup | grep ':514 '
tcp   LISTEN 0      25         127.0.0.1:514        0.0.0.0:*    users:(("rsyslogd",pid=1097,fd=4))

• A The input is bound to 127.0.0.1 — it only accepts the machine itself.
• B The lines will come later — rsyslog takes them in batches.
• C Port 514 is closed — rsyslog does not listen on it.
• D rsyslog listens on UDP, and the machines send over TCP.