Catch a message queue id
Practitioner 20 ptsGoal: Push a message through DATA and read the queue id the server returns.
Capture it yourself — real SMTP needs a terminal
- Start Wireshark on your active interface with filter
tcp.port == 2525(orsudo tcpdump -i any -w cap.pcap port 2525). - Run this against the real SMTP server on this box:
printf 'EHLO me\r\nMAIL FROM:<a@b.c>\r\nRCPT TO:<x@sentinel.lab>\r\nDATA\r\nhi\r\n.\r\nQUIT\r\n' | nc ctf.nitaimaarek.com 2525
Stop the capture and Follow → TCP Stream. After the message body, the server replies 250 … queued as … — that queue id is the answer.
No nc? On Linux/macOS try ncat, or bash: exec 3<>/dev/tcp/ctf.nitaimaarek.com/2525. The exchange is plaintext, so it's fully readable in your capture — that's the whole point.
Hints
Open in order — they nudge, not solve.
Hint 1
Send a whole SMTP conversation and capture it. The widget's printf … | nc one-liner does it in one shot.
Hint 2
After you end the message with a lone ., the server replies 250 … queued as ….
Hint 3
That SMTP-QUEUE-… id is the answer.