In email logs, which item uniquely identifies a single message across systems?

In email logs, which item uniquely identifies a single message across systems?

• A. Date and time the message was sent
• B. Unique message identifier
• C. Attachments sent with the e-mail message
• D. Contents of the e-mail message

Answer: (B)

A unique message identifier is the reliable way to tag a single email across different systems. In practice, emails include a header field called Message-ID, assigned by the sending system and designed to be globally unique. This ID travels with the message and remains associated with it as it moves through servers, archives, and logs, making it the definitive fingerprint for that particular message. Dates and times can collide or be recorded with different time zones and clock inaccuracies, so they’re not a dependable unique marker. Attachments can be identical across different messages, and the contents of messages can be the same or changed, which means they don’t provide a guaranteed unique identity.

A unique message identifier is the reliable way to tag a single email across different systems. In practice, emails include a header field called Message-ID, assigned by the sending system and designed to be globally unique. This ID travels with the message and remains associated with it as it moves through servers, archives, and logs, making it the definitive fingerprint for that particular message.

Dates and times can collide or be recorded with different time zones and clock inaccuracies, so they’re not a dependable unique marker. Attachments can be identical across different messages, and the contents of messages can be the same or changed, which means they don’t provide a guaranteed unique identity.