On Mon, 05 Feb 2001 18:28:53 -0500,
"L.D. Best" <[EMAIL PROTECTED]> wrote:
>
> I wasn't going to reply, because it would just be another case of "no
> win" ...
>
> I will, instead, simply state that my ISP made clear a number of things
> about the types of firewall protection they have:
>
> 1. The SMTP server will not "open relay."
>
> 2. If the need arose for me to telnet into the servers, for mail
> tossing from foreign site [like when I'm stuck in the VA hospital], they
> would consider giving me a username & password that would allow it;
> without the username & password, it would not be possible to do.
I assume you are talking about telnetting to port 25 (smtp) and not
port 23 (telnet).
Before all this authentication business, they would have probably
told you to use the smtpserver at the VA hospital, period.
Authentication is less restrictive than IP-based protection. Also,
users don't have to change the smtpserver setting in their e-mail
client.
> 3. Anyone who believes such to not be the case can attempt to telnet
> into the SMTP server and see what happens.
So far, I believe you. :-)
> If [as I suspect] you can't
> even get close using just "go-concepts.com," and you are bound and
> determined to prove me wrong, please ask for the numeric address and I
> will provide it. If you *can* manage to break in, then my ISP would
> like to know that, and they won't get angry at you unless you also
> decide to send out a spew of spam.
I don't think it's a question of trying to prove anyone wrong, but of
trying to learn something. So, as long as port 25 is not blocked on my
network, surely, I should be able to telnet to one or more smtpservers
at go-concepts.com that will accept mail for you or anyone else at
go-concepts.com. Otherwise, how could anyone send you e-mail? Let's try
a couple.
(note - ESTMP without AUTH)
# telnet go-concepts.com 25
Trying 207.40.122.20 ...
Connected to go-concepts.com.
Escape character is '^]'.
220 ns1.go-concepts.com ESMTP Sendmail 8.11.0/8.11.0;
Tue, 6 Feb 2001 01:11:35 -0500
EHLO nyx10.nyx.net
250-ns1.go-concepts.com Hello [EMAIL PROTECTED] [206.124.29.2],
pleased to meet you
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-SIZE 7000000
250-DSN
250-ONEX
250-ETRN
250-XUSR
250 HELP
mail from:<[EMAIL PROTECTED]>
250 2.1.0 <[EMAIL PROTECTED]>... Sender ok
rcpt to:<[EMAIL PROTECTED]>
250 2.1.5 <[EMAIL PROTECTED]>... Recipient ok
quit
221 2.0.0 ns1.go-concepts.com closing connection
Connection closed by foreign host.
#
(note - ESTMP with AUTH)
#telnet mail1.go-concepts.com
Trying 207.40.122.7 ...
Connected to mail1.go-concepts.com.
Escape character is '^]'.
220 mail1.go-concepts.com ESMTP Sendmail 8.11.1/8.11.1;
Tue, 6 Feb 2001 00:13:03 -0500
EHLO nyx10.nyx.net
250-mail1.go-concepts.com Hello nyx10.nyx.net [206.124.29.2],
pleased to meet you
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-SIZE 7000000
250-DSN
250-ONEX
250-ETRN
250-XUSR
250-AUTH DIGEST-MD5 CRAM-MD5
250 HELP
mail from:<[EMAIL PROTECTED]>
250 2.1.0 <[EMAIL PROTECTED]>... Sender ok
rcpt to:<[EMAIL PROTECTED]>
250 2.1.5 <[EMAIL PROTECTED]>... Recipient ok
quit
221 2.0.0 mail1.go-concepts.com closing connection
Connection closed by foreign host.
#
Of course, I cannot use your ISP's mailservers to send mail to
third-parties, but this is always the case with closed relays
whether or not you have a password or some other method to do
so. Here's an example.
(note - Relaying denied without AUTH)
#telnet go-concepts.com 25
Trying 207.40.122.20 ...
Connected to go-concepts.com.
Escape character is '^]'.
220 ns1.go-concepts.com ESMTP Sendmail 8.11.0/8.11.0;
Tue, 6 Feb 2001 02:20:23 -0500
ehlo nyx10.nyx.net
250-ns1.go-concepts.com Hello [EMAIL PROTECTED] [206.124.29.2],
pleased to meet you
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-SIZE 7000000
250-DSN
250-ONEX
250-ETRN
250-XUSR
250 HELP
mail from:<[EMAIL PROTECTED]>
250 2.1.0 <[EMAIL PROTECTED]>... Sender ok
rcpt to:<[EMAIL PROTECTED]>
550 5.7.1 <[EMAIL PROTECTED]>... Relaying denied
quit
221 2.0.0 ns1.go-concepts.com closing connection
Connection closed by foreign host.
#
By the way, I normally use my ISP's smarthost (plain old-fashioned
IP-based closed relay) to send e-mail, but since this discussion
came up, I've been using POP-before-SMTP at gmx.net (a free e-mail
service) with my DOS mailers.
Howard E.
--
DOS TCP/IP * <URL:http://www.ncf.ca/~ag221/dosppp.html>
