Linux and Open Source | Main / Sending-Mail-Via-Telnet-to-Port-25-to-Test-SMTP-Communication

Reference : http://www.ietf.org/rfc/rfc2821.txt
Make sure that the host from which you are trying to do telnet can connect to the server.
Connect to the internet.
Step 1 telnet itmission.org 25
Enter the following command to connect to the mail server using telnet command.
Below definitely see the '220' part. It is an indication that the server is ready to service your request.
Step 2 Now the server expects you to identify yourself- here you need to enter your hostname if you are using dialup connection or if you have a domain name then your domain name.

EHLO shibu-laptop

We need to tell the server our name and the server will return back to us with his name :)

250-earth.assuredhost.com Hello shibu-laptop [xx.xx.xx.xxx]

step 3 Next give the server your e-mail address.

MAIL FROM:shibucv@shibu-laptop.com

Step 4Tell the server who you want to send the e-mail to.

rcpt to: info@aol.com

Step 5 Use data command to type in the email
Step 6When you finish your e-mail, press [ENTER], then a '.'(dot), and again an [ENTER]. This tells the server that you have finished the e-mail, and it can send it.
Step 7Send another mail using RCPT command and DATA command with the same connection or quit using QUIT command.
Please see some commands have not be run below.


shibu@shibu-laptop:~$ telnet itmission.org 25
Trying 209.67.221.77...
Connected to itmission.org.
Escape character is '^]'.

help
220-earth.assuredhost.com ESMTP Exim 4.68 #1 Wed, 30 Jan 2008 07:23:09 -0800
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.
214-Commands supported:
214 AUTH STARTTLS HELO EHLO MAIL RCPT DATA NOOP QUIT RSET HELP

EHLO shibu-laptop

250-earth.assuredhost.com Hello shibu-laptop [xx.xx.xx.xxx]
250-SIZE 52428800
250-PIPELINING
250-AUTH PLAIN LOGIN
250-STARTTLS
250 HELP

MAIL FROM:shibu-laptop.com
501 shibu-laptop.com: sender address must contain a domain

MAIL FROM:shibucv@aol.com
250 OK

quit

221 earth.assuredhost.com closing connection
Connection closed by foreign host.
shibu@shibu-laptop:~$