postfix-users March 2012 archive
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postfix-users: Re: SMTP commands Auth

Re: SMTP commands Auth

From: Rachid Abdelkhalak <rachid_at_nospam>
Date: Sun Mar 18 2012 - 18:51:03 GMT
To: Reindl Harald <h.reindl@thelounge.net>

On Sun, 18 Mar 2012, Reindl Harald wrote:

>
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> Am 18.03.2012 19:27, schrieb Rachid Abdelkhalak:
>>>> If it's not possible, Is there any additional filters can i apply authenticate users trying to use SMTP Commands to
>>>> send emails from the server using Telnet port 25?
>>>
>>> there is simply no differnce between telnet and any other MUA
>>> you have restricted relay for authenticated users (hopefully
>>> or you should shut down the machine) or not, the MTA is not interested
>>> in which client submits a message
>>
>> I'm using SMTP Auth for all connections coming from networks NOT in mynetworks. When i'm using a clinent such as
>> Outlook, Alpine... from an IP not in mynetworks, i'm prompted fot authentication. But when i'm doing a telnet from
>> the same IP, i'm not and i'm allowed to send emails from my CEO @myowndomain.tld to any address for example.
>
> i guess you do not understand SMTP Authentication
>

Maybe, i'm counting on you to have things more clear

> you are NOT prompted if the RCPT is in your own domains
> this is because you are not try to relay
> that way mail delivery works from other MTA's

The RCPT is not in my domain.

For example, if i connect to my server

telnet myserver 25
ehlo
mail from:<myCEO@mydomain.com>
rcpt to:<externaladdress@otherexternaldomain.com>
data
This is a test, please do not respond
.
quit

With this test, i was able to send email from my CEO address to an
external email address using my server.

That's what i'm trying to prvent.

Thank you

>
> again: there is no difference between telnet and any other MUA
>
> spoofing protections has nothing to do with SMTP Auth
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