RE: can the telnet command be automated?

Scott,

Can you point me to where I might find an "email software solution. I see a
lot of php stuff on the net for email validation, but im not sure they cover
the issue you brought up (with exception to #2).

I have your LIBHTTP library installed, but not sure if I can use it for this
purpose. I don't see any example (at least that I can figure out) that might
come close to doing what I am looking for.



-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Klement
Sent: Tuesday, November 09, 2010 2:53 PM
To: Midrange Systems Technical Discussion
Subject: Re: can the telnet command be automated?

Hi Tim,

That's not really a valid/reliable way to check an e-mail address.
While you can _probably_ get it to work, any e-mail that happens to
contain a telnet IAC character will cause things to go haywire.

Furthermore, you are telling the e-mail server that you are going to
send a message, and then assuming that it will reject the message if the
destination address if incorrect. That's not reliable.

1) You need to make sure you're connecting to a valid mail-exchanger for
the destination address. That's not the same as a simple DNS lookup on
'yourdomain.com', you need to look up the MX records, and only fall back
to the address (A record) if the MX records aren't found. Telnet
clients won't do that.

2) Many sites will accept messages for invalid e-mail addresses, and
then either silently discard them, or forward them to an administrator,
or attempt to relay the message. You can't simply assume that an e-mail
address is valid just because it's accepted.

3) The IAC character thing I mentioned.

Want a better way? I'd suggest using (or writing) e-mail software
instead of telnet software. That'll give you the ability to solve
problems 1 & 3, above.

There's no solution for #2. There simply isn't a way to completely
validate an e-mail address, aside from sending mail to it and getting a
response back. This has been discussed dozens and hundreds and millions
and zillions of times on Midrange.com. People hide their e-mail
addresses to avoid spam.


On 11/9/2010 12:43 PM, tim.dclinc@xxxxxxxxx wrote:

I found a technique to validate an email address using telnet port 25 as
follows:

telnet smtpserver:25

then type the following

helo<yourdomain.com>
mail from:<info@xxxxxxxxxxxxxx>
rcpt to:<jimbsa2aa4@smtpserver>


If there is a better way of doing this, im up for it.

Here are two sites for reference
http://verify-email-address.org
http://www.barattalo.it/demo/dosmtpvalidation.php#


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Klement
Sent: Tuesday, November 09, 2010 12:59 PM
To: Midrange Systems Technical Discussion
Subject: Re: can the telnet command be automated?

I thought you were trying to automate a telnet connection? If so, why
are you connecting to an SMTP (e-mail) port?!


On 11/9/2010 10:22 AM, tim.dclinc@xxxxxxxxx wrote:

Im trying to work with PASE TELNET using the technique discussed, but it
locks up and doesn't complete the script.

Here is the qsh command I am using
QSH CMD('(/curl -v telnet://74.125.45.27:25</tmp/pase/stdin.txt )')

Here is the script file.
HELO<barattalo.it>
MAIL FROM:<info@xxxxxxxxxxxx>
RCPT TO:<sample@xxxxxxxxxx>

Here is the output:
* About to connect() to 74.125.45.27 port 25
* Trying 74.125.45.27... connected
* Connected to 74.125.45.27 (74.125.45.27) port 25
220 mx.google.com ESMTP b20si14035801ana.185
250 mx.google.com at your service

It just sits on this display. I cant get out of the session without using
System Request opt 2

Any suggestions?