SGSPECTER.GHOSTCOMMUNITY EDITION
← LABS
// GUIDED TRAINING · Network

Mail Relay Audit

SMTP relay controls

Medium350 PTSOFFLINE SIMULATION
// 01 · LEARN

SMTP RELAY CONTROLS

Mail servers should distinguish local delivery from relaying mail to external recipients. An open relay can be abused to send unsolicited messages.

LEARNING GOAL

Identify the misconfiguration in the synthetic evidence and explain a defensive correction.

// 02 · INVESTIGATE

EVIDENCE

220 mail.ghost.invalid ESMTP training
EHLO student.ghost.invalid
250 AUTH PLAIN
MAIL FROM:<test@outside.invalid>
250 OK
RCPT TO:<target@elsewhere.invalid>
250 Relay accepted (unauthenticated)
review_marker=relay_requires_policy
HINT

The recipient is outside the server's local domain.

// 03 · PRACTICE

KNOWLEDGE CHECK

Which policy mistake allows relay without authentication?

// 04 · CAPTURE FLAG

Submit the review marker in SG{marker} format.

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