Support HackTricks and get benefits! - Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)! - Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family) - Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com) - **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.** - **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**
**Extracted from:** [**https://serversmtp.com/smtp-commands/**](https://serversmtp.com/smtp-commands/) **HELO**\ It’s the first SMTP command: is starts the conversation identifying the sender server and is generally followed by its domain name. **EHLO**\ An alternative command to start the conversation, underlying that the server is using the Extended SMTP protocol. **MAIL FROM**\ With this SMTP command the operations begin: the sender states the source email address in the “From” field and actually starts the email transfer. **RCPT TO**\ It identifies the recipient of the email; if there are more than one, the command is simply repeated address by address. **SIZE**\ This SMTP command informs the remote server about the estimated size (in terms of bytes) of the attached email. It can also be used to report the maximum size of a message to be accepted by the server. **DATA**\ With the DATA command the email content begins to be transferred; it’s generally followed by a 354 reply code given by the server, giving the permission to start the actual transmission. **VRFY**\ The server is asked to verify whether a particular email address or username actually exists. **TURN**\ This command is used to invert roles between the client and the server, without the need to run a new connaction. **AUTH**\ With the AUTH command, the client authenticates itself to the server, giving its username and password. It’s another layer of security to guarantee a proper transmission. **RSET**\ It communicates the server that the ongoing email transmission is going to be terminated, though the SMTP conversation won’t be closed (like in the case of QUIT). **EXPN**\ This SMTP command asks for a confirmation about the identification of a mailing list. **HELP**\ It’s a client’s request for some information that can be useful for the a successful transfer of the email. **QUIT**\ It terminates the SMTP conversation.
Support HackTricks and get benefits! - Do you work in a **cybersecurity company**? Do you want to see your **company advertised in HackTricks**? or do you want to have access to the **latest version of the PEASS or download HackTricks in PDF**? Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)! - Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family) - Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com) - **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.** - **Share your hacking tricks by submitting PRs to the** [**hacktricks github repo**](https://github.com/carlospolop/hacktricks)**.**