Re: Email questions

Giganews Newsgroups
Subject: Re: Email questions
Posted by:  Remy Lebeau (TeamB) (
Date: Mon, 21 Nov 2005

"Sumer" <sume…> wrote in message

> Then talk with the server with the SMTP commands.

Which commands are you sending exactly?  How exactly are are identifying
yourself to the server?

> But eveytime I try this on the servers, I get error message when
> I wrote RCPT TO: x… The server says that relaying
> denied. Does this error occurs because I am trying to send the mail
> to the wrong mx machine?

No.  It means that you are not an authorized user on that server and thus
are not allowed to send messages through it.

> does the server make this DNS reverse query on my IP Address and
> the domain name that I have given to the HELO myDomain command
> or something else?

That is a possibility.

> 2)Also I am curious about the SMTP Autharization.I use Ethereal
> to inspect the transaction between the SMTP server and my MUA
> (Outlook Express currently).I inspect all the SMTP commands,
> when I send the mail in Outlook.And I cannot find any clue about
> where my username  and password are posted to the server.

If you don't see them then they likely are not being sent at all.  The SMTP
protocol does not require authentication (though particular servers might).
The EHLO response will specify which authentication schemes the server
supports, however.

> I can only see the specific SMTP commands like HELO, MAIL
> FROM, DATA...etc.

If HELO is being used then no authentication can be performed, since EHLO
has to be used instead of HELO in order to know what authentication schemes
are supported on the server.

> 3)I see some transaction examples on the internet like: AUTH
> these encryption methods being used to transfer my username
> and password?

No.  If they were, you would see them in the Ethereal log with the other
SMTP commands.  The username/password data would be encrypted but you would
still see the commands themselves being sent.

> And I connect Internet using dynamic IP adress(for the questions above).

That in itself can cause servers to reject messages as well.  Some servers
do not allow connections from dynamic IPs that were not assigned from the
same service that is running the SMTP server.



In response to

Email questions posted by Sümer on Sat, 19 Nov 2005