SMTP

• Simple mail transfer protocol

• port 25

• Telnet - HELO/EHLO

  • telnet 10.129.14.128 25

• VRFY

  • can be used once connected by telnet, to confirm the existence of the user

  • vrfy root

• nmap

  • sudo nmap 10.129.14.128 -sC -sV -p25

• Nmap - Open Relay

  • nmap 10.129.14.128 -p25 --script smtp-open-relay -v