SMTP Commandos mit dazugehörigens Referenz RFC's gibt es hier. Da es eine recht lange Tabelle ist kommt sie auf der der nächsten Seite.
| Command | Description | RFC |
| 8BITMIME | Use 8-bit data | RFC 1652 |
| ATRN | Authenticated TURN | RFC 2645 |
| AUTH | Authentication | RFC 2554 / RFC 4954 |
| BDAT | Binary data | RFC 3030 |
| BINARYMIME | Binary MIME | RFC 3030 |
| BURL | Remote Content | RFC 4468 |
| CHECKPOINT | Checkpoint/Restart | RFC 1845 |
| CHUNKING | Chunking | RFC 3030 |
| DATA | Data | RFC 2821 |
| DELIVERBY | Delivery within prescribed period | RFC 2852 |
| DSN | Delivery Status Notification | RFC 3461 |
| EHLO | Extended Hello | RFC 2821 |
| ENHANCEDSTATUSCODES | Enhanced Status Codes | RFC 2034 |
| ETRN | Extended Turn | RFC 1985 |
| EXPN | Expand | RFC 2821 / RFC 5321 |
| FUTURERELEASE | Future Message Release | RFC 4865 |
| HELO | Hello | RFC 2821 |
| HELP | Help | RFC 2821 / RFC 5321 |
| RFC 2821 | ||
| MTRK | Message Tracking | RFC 3885 |
| NO-SOLICITING | Notification of no soliciting | RFC 3865 |
| NOOP | No operation | RFC 2821 |
| ONEX | One message transaction only | |
| PIPELINING | Command Pipelining | RFC 2920 |
| QUIT | Quit | RFC 2821 |
| RCPT | Recipient | RFC 2821 |
| RSET | Reset | RFC 2821 |
| SAML | (deprecated) Send and mail | RFC 821 / RFC 2821 |
| SEND | (deprecated) Send | RFC 821 / RFC 2821 |
| SIZE | Message size declaration | RFC 1870 |
| SOML | (deprecated) Send or mail | RFC 821 / RFC 2821 |
| STARTTLS | Start TLS | RFC 3207 |
| SUBMITTER | SMTP Responsible Submitter | RFC 4405 |
| TURN | (deprecated) Turn | RFC 821 / RFC 2821 |
| UTF8SMTP | Internationalized email address | RFC 5336 |
| VERB | Verbose | |
| VRFY | Verify | RFC 2821 |
Siehe auch SMTP Reply Codes