Re: Recipient validation - WAS: Re: Moderated posts?
On Thu, Oct 16, 2014 at 9:34 PM, Tanstaafl <tanstaafl@libertytrek.org> wrote:
> On 10/16/2014 7:40 AM, Joel Rees <joel.rees@gmail.com> wrote:
>> On Thu, Oct 16, 2014 at 7:58 PM, Tanstaafl <tanstaafl@libertytrek.org> wrote:
>>> > On 10/15/2014 8:37 PM, Jerry Stuckle <jstuckle@attglobal.net> wrote:
>>>> >> Tanstaafl couldn't answer it, and you can't either, because it's not
>>>> >> violating any.
>>> >
>>> > I did answer it, you just ignored it or don't understand it.
>>> >
>>> > Quote:
>>> >
>>> > "You do not have to violate an RFC to break SMTP."
>>> >
>>> > Here is a real world example:
>>> >
>>> > Improperly configured TCP filtering features on firewalls and routers
>>> > don't violate any specific RFC, but they certainly can break SMTP (and
>>> > other things too).
>> Thus, we can understand that you are an idealist that would rather see
>> your version of SMTP rules be followed by everyone than try to follow
>> the RFC yourself.
>>
>> Where are your SMTP rules spelled out, by the way?
>
> Ok, I just went and looked it up, and lo and behold...
>
> RFC 2821 is the controlling RFC if I'm not mistaken...
>
> https://tools.ietf.org/html/rfc2821
>
> In there you'll find this:
>
> " The second step in the procedure is the RCPT command.
>
> RCPT TO:<forward-path> [ SP <rcpt-parameters> ] <CRLF>
>
> The first or only argument to this command includes a forward-path
> (normally a mailbox and domain, always surrounded by "<" and ">"
> brackets) identifying one recipient. If accepted, the SMTP server
> returns a 250 OK reply and stores the forward-path. If the recipient
> is known not to be a deliverable address, the SMTP server returns a
> 550 reply, typically with a string such as "no such user - " and the
> mailbox name (other circumstances and reply codes are possible).
> This step of the procedure can be repeated any number of times."
>
> So, how do you 'interpret' the pertinent part:
>
> "If the recipient is known not to be a deliverable address, the SMTP
> server returns a 550 reply, typically with a string such as "no such
> user - " and the mailbox name (other circumstances and reply codes are
> possible)."
>
> ?
>
> Sounds to me like a mandate to reject invalid recipients at the RCPT-TO
> stage.
Well, I'll tell you what. Before I try to engage with you on this, I'm
going to do my part and re-read RFCs 5321, 5322, 4409, and BCP 14 and
several others referred to therein, completely, and make sure I
understand them.
I strongly encourage you to do the same.
--
Joel Rees
Be careful when you see conspiracy.
Look first in your own heart,
and ask yourself if you are not your own worst enemy.
Arm yourself with knowledge of yourself.
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