25 - SMTP

# Connection and test using telnet
telnet <IP> 25

EHLO <IP>
VRFY root
EXPN root
Mail from: me@test.com
To: root@test.com
Data:
Subject: Message
Hi,

Just a test message.


(Double carriage return)

# using smtp-user-enum script
smtp-user-enum -M VRFY -U users.txt -t <IP>