Re: telnet on port 25

From: Frye, Matthew (Matthew.Frye@REXHEALTH.COM)
Date: Mon Apr 19 2004 - 09:02:19 EDT


> Hi *,
> I am trying to telnet to our mail server(Win NT) from
> an AIX box
> using port 25. When i connect it gives me a message saying
> ready but no
> prompt to execute any commands, and it does not even ask me
> the username and
> a password. I have never connected on port 25 using telnet
> before. Is this
> the way it works or am i doing something wrong. Pl find the
> output i have
> got when executing those commands.
>
>
> telnet> open 195.183.212.12 25
> Trying...
> Connected to 195.183.212.12.
> Escape character is '^]'.
> 220 <hostname> ESMTP Server (Microsoft Exchange Internet Mail Service
> 5.5.2657.72) ready

Generally, telnet'ing to port 25 is used as a diagnostic tool to determine
the status of a mail server. If you receive a ready, then your mail server
is able to receive incoming mail. You would not (and should not) receive a
login prompt at all. Telnet'ing to 25 can also be used to send fake mail to
a server, but usually it has a significantly different look from regular
mail, because more header information* is passed when an actual mail server
connects to that machine.

Matt Frye
Sr. Systems Programmer, RS/6000 Group
Rex Healthcare
(919) 784-3791

*deliberately vague

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