How to perform a Telnet Test?

To manually perform a mail transaction using telnet, perform the following steps. IMPORTANT: If you make a typographical mistake, do not use backspace, which can send control characters that will cause a syntax error. Instead, quit and start over. The explanation and instruction portion is in italics, and what the computer's responses should be are in bold.

Telnet Test

From a Command prompt, type:

telnet mailin-01.mx.aol.com 25

This specifies to telnet to port 25 on an AOL mail host.

The mail host identifies itself. This should be accompanied by several lines of introductory text (sample below):

220-mtain-di02.r1000.mx.aol.com ESMTP Internet Inbound
220-AOL and its affiliated companies do not
220-authorize the use of its proprietary computers and computer
220-networks to accept, transmit, or distribute unsolicited bulk
220-e-mail sent from the internet.
220-Effective immediately:
220-AOL may no longer accept connections from IP addresses
220 which no do not have reverse-DNS (PTR records) assigned.
421 4.4.2 mtain-di02.r1000.mx.aol.com Error: timeout exceeded
Connection closed by foreign host.

''This is the standard greeting text issued after any successful connection to the AOL mail system. This text will be shown after a connection is made regardless of the state of the PTR record on the connecting IP. The last 2 lines are considered normal and do not indicate an error with your connection. If in doubt, you can check to see if you have reverse DNS (rDNS).''

Type:

EHLO example.com

Example.com specifies your mail server's domain. Your host's name will be repeated back to you by the AOL mail server, preceded by the name of the AOL server you are connecting to. For example:

250-rly-dd06.mx.aol.com yourhostname.example.com

then you will see: 250 HELP - this is normal. Keep going.

Type:

MAIL FROM: <you@example.com>

where you@example.com indicates the address the mail should appear to be from. Note: You must include the < > signs. If you type it correctly, you will see: 250 OK. If not, you will probably get a SYNTAX ERROR.

Type:

RCPT TO: <yourrecipient@aol.com>

Note: You must include the equality(< >) signs. If you type it correctly, you will see: 250 OK. If not, you will probably get a SYNTAX ERROR.

Type:

DATA

and you will see: START MAIL INPUT, END WITH "." ON A LINE BY ITSELF

Type a brief message, followed by Type a period (dot). Hit again. (Type a period on a line by itself, then hit ENTER.) You will see:

250 OK

A successful transaction should appear. For example:

telnet mailin-01.mx.aol.com 25
Trying 205.188.159.57...
Connected to mailin-01.mx.aol.com.
Escape character is '^]'.
220-rly-da06.mx.aol.com ESMTP mail_relay_in-da06.3; Mon, 09 Feb 2014 13:54:08 -0500
220-America Online (AOL) and its affiliated companies do not
220-     authorize the use of its proprietary computers and computer
220-     networks to accept, transmit, or distribute unsolicited bulk
220-     e-mail sent from the internet.  Effective immediately:  AOL
220-     may no longer accept connections from IP addresses which
220      have no reverse-DNS (PTR record) assigned.
EHLO example.com
250-rly-dd06.mx.aol.com yourhostname.example.com
250 HELP
MAIL FROM: <you@example.com>
250 OK
rcpt to: <yourrecipient@aol.com>
250 OK
DATA
354 START MAIL INPUT, END WITH "." ON A LINE BY ITSELF
testing 123
.
250 OK