TLDR guide to sending an email with telnet

raw_email.md

1. Connect to the hashbang mail server with telnet

   > ssh sf1.hashbang.sh telnet localhost 25
   Trying ::1...
   Connected to localhost.
   Escape character is '^]'.
   220 sf1.hashbang.sh ESMTP Postfix (Debian/GNU)
   

2. Announce yourself to the mail sever

   ELHO hashbang.sh
   

   The server will respond with a list of protocals it supports:

   250-sf1.hashbang.sh
   250-PIPELINING
   250-SIZE 52428800
   250-VRFY
   250-ETRN
   250-STARTTLS
   250-ENHANCEDSTATUSCODES
   250-8BITMIME
   250 DSN
   

3. Tell the server who you want to send mail as

   MAIL FROM:[email protected]
   

   Note: you can put literally any email you want here. This is like a return address on an envelope. Most email servers will blindly let you impersonate anyone. We call this email "spoofing".

4. Tell the server who you want to receive the mail

   RCPT TO: [email protected]
   

5. Tell the server the body of the message you want to send

   Note: end with a period on a line by itself

   DATA
   Subject: some subject
   
   My really awesome message here
   

6. Send message

   .
   

   Just a single period on a line by itself lets the server know you are done.

   Go check your inbox!

   Depending on who you spoofed, it may or may not be in spam.

   Please don't abuse this, and be mindful of the laws in your local area.