How to Send an email using Telnet in CentOS

sudo apt install telnet

sudo yum install telnet

telnet targetserver.tld 25

HELO sourceserver.tld 

MAIL FROM: username@sourcedomain.tld

RCPT TO: username@example.com

DATA 

Subject: Sending an email using  SMTP through telnet 

Hi, 

This is just a Test Email ? You may disregard this? 

regards;

Mr. Y

.

Note: We can start writing some subject and body. To do that we need to use the DATA command. First type DATA followed by Subject: and the body. Once done, enter " . "  (without quote)to send the email to be queued.