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Asking ChatGPT to analyze a Mailinator SMTP Log

ChatGPT - Open AI

We asked ChatGPT to analyze a random Public Mailinator SMTP Log. It gave some pretty impressive results, especially since the SMTP Log in this format is simply formatted for humans, not machines. (The Mailinator API allows you to get and SMTP log formatted in JSON)

Analyze this SMTP transaction – explain anything interesting:

0ms SOCKET_OPEN Connection from:

0ms OUTGOING --> 220 mail.mailinator.com ESMTP Postfix

74ms INCOMING <-- EHLO m45-84.mailgun.net

74ms OUTGOING --> 250-mail.mailinator.com 250-8BITMIME 250-STARTTLS

250 Ok


149ms OUTGOING --> 220 Ready to start TLS


297ms INCOMING <-- EHLO m45-84.mailgun.net

297ms OUTGOING --> 250-mail.mailinator.com 250-8BITMIME 250-STARTTLS 250 Ok


370ms OUTGOING --> 250 Ok

442ms INCOMING <-- RCPT TO:test123456@mailinator.com

442ms OUTGOING --> 250 Ok


515ms OUTGOING --> 354 End data with .

515ms DATA [ Data Delivery Starts ]

1129ms DATA [ 55348 data bytes received ]

1129ms MSG_SAVED Public Message Stored: test123456-1687514749-223267893

1132ms OUTGOING --> 250 Ok

1211ms INCOMING <-- QUIT


ChatGPT Says:

This is an SMTP (Simple Mail Transfer Protocol) transaction log that shows the communication between a client and a server during an email exchange. Let’s analyze the transaction step by step:

0ms: The connection is established from the IP address to the server at mail.mailinator.com.

0ms OUTGOING: The client sends the initial greeting to the server with the message “220 mail.mailinator.com ESMTP Postfix.”

74ms INCOMING: The server responds to the client’s greeting with “EHLO m45-84.mailgun.net,” indicating that it supports the Extended Hello (EHLO) command.

74ms OUTGOING: The client acknowledges the server’s response and sends its capabilities using the EHLO command. It includes the features “250-mail.mailinator.com 250-8BITMIME 250-STARTTLS 250 Ok.”

149ms INCOMING: The server requests a secure connection by sending the command “STARTTLS.”

149ms OUTGOING: The client agrees to start TLS (Transport Layer Security) encryption and responds with “220 Ready to start TLS.”

297ms: TLS becomes active, indicating that the communication between the client and server is now encrypted.

297ms INCOMING: After the TLS handshake, the server expects the client to re-establish the connection and send another EHLO command.

297ms OUTGOING: The client re-establishes the connection and sends its capabilities again with the EHLO command.

370ms INCOMING: The server receives the EHLO command from the client.

370ms OUTGOING: The client informs the server that it intends to send an email from the address “bounce+c86a4e.66b717-test123456=mailinator.com@email.jumia.com.gh” using the 8-bit MIME format.

442ms INCOMING: The server acknowledges the sender’s address and requests the recipient’s address with the command “RCPT TO:test123456@mailinator.com.”

442ms OUTGOING: The client confirms the recipient’s address.

515ms INCOMING: The server receives the command “DATA” from the client, indicating that the email’s content will follow.

515ms OUTGOING: The client acknowledges the server’s request and allows the server to expect the email’s content by sending “354 End data with <CR><LF>.<CR><LF>.”

515ms DATA: The email’s data delivery starts.

1129ms DATA: The server indicates that it has received 55,348 data bytes of the email.

1129ms MSG_SAVED: The server stores the public message with the unique identifier “test123456-1687514749-223267893.”

1132ms OUTGOING: The server confirms the successful receipt and storage of the email.


1212ms SOCKET_CLOSED: The socket, representing the connection between the client and server, is closed.

Interesting observations from this transaction:

  1. The client initially establishes a connection and negotiates the use of TLS encryption for secure communication.
  2. The server supports features like 8BITMIME (for sending 8-bit data) and STARTTLS (for upgrading to a secure connection).
  3. The client and server engage in a successful TLS handshake, establishing an encrypted connection.
  4. The client and server exchange the necessary commands (EHLO, MAIL FROM, RCPT TO, DATA) to send an email.
  5. The server acknowledges the successful receipt and storage of the email.

Great ! You can find the SMTP Log for every Mailinator Email on the Email viewing page using the “SMTP Log” Tab.

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