Re: E-mail Scramblers

JRS: In article <jvkqa3-8eb.ln1@xxxxxxxxxxxxxxxxxxx>, dated Fri, 27 Jan
2006 22:55:11 remote, seen in news:comp.infosystems.www.authoring.html,
Nick Kew <nick@xxxxxxxxxxxxxxxxxxx> posted :
>Dr John Stockton wrote:
>
>>
>> My ISP provides what I describe; mail for merlyn is not rejected
>> immediately, but only when I connect to the ISP
>
>Whoosh!
>
>What happens between you and your ISP is utterly immaterial.
>If it's waiting for you on your ISP's server, then IT HAS ALREADY
>BEEN ACCEPTED FROM THE SPAMMER.
>
>Bouncing email that has been accepted by your ISP's server puts YOU
>on the level of the spammer - because the recipient of the bounce
>(if any) is an innocent victim. And dropping it is also problematic,
>because any false positive you get will be dropped without the
>sender ever knowing. Just don't do it.


When at my ISP, it has not been accepted by the Internet host that it is
directed to.

When at my ISP, it has not reached the Internet host that it is directed
to.

When at my ISP, it is merely being held in an intermediate machine until
it can be passed on to its destination.

My ISP's mail system knows NOTHING about what left-hand parts are valid
with @merlyn.dcu .

Merlyn owns (well, leases) the whole of a dotted quad (though legitimate
stuff for www.merlyn.dcu does not reach here).


Please look back to my first post in this branch of the thread - well,
I'd better repeat the relevant part :-


<QUOTE>
>You can't. Once you are on a list, you're a gonner. You don't even
>need to publish your address anywhere, spammers will target ISPs with
>random addresses to see those that work and those that don't. Any that
>aren't bounced almost immediately must be real.

They may be considered real, but it's not always a valid assumption.
Dial-up Internet hosts cannot reject until connected.
</QUOTE>


Read carefully, and you will see that I was saying ONLY that the lack of
an immediate bounce does not necessarily mean that the address is valid.

Let X be a 15-character random alphanumeric string.

Then X at aol.com is (almost certainly) a non-deliverable address; a
spammer probing it should receive an immediate bounce.

But X at merlyn.dcu is (certainly) a non-deliverable address; a
spammer probing it will NOT receive an immediate bounce, but will
receive a bounce after I next Connect.


REMEMBER :

The point under consideration is the timing of a bounced probe, and a
probe needs to have a return address such that the spammer will see the
bounce.

The decision as to what happens to each mail sent to @merlyn.dcu is
taken here in this room, by me and my machine; we set our policy before
connecting, but that policy can only be observed from outside this room
while a connection is active.

--
© John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v4.00 MIME ©
Web <URL:http://www.uwasa.fi/~ts/http/tsfaq.html> -> Timo Salmi: Usenet Q&A.
Web <URL:http://www.merlyn.demon.co.uk/news-use.htm> : about usage of News.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.
.

Relevant Pages

  • Re: Should ISPs send bounceback on mail to non-existent address?
    ... With that immediate determination, ... informative and relevant bounce message generated by their own mail server. ... I think an ISP that accepts all mail transfers and passes up ...
    (comp.mail.misc)
  • Re: Why dont ISPs Stop all Viruss ?!?
    ... Do not use its' bounce feature since it just verifies ... to the spammer that your email address may be real. ... and bouncing it back to the ISP that sent it. ...
    (alt.support.diabetes)
  • Re: OE6 rejects some messages
    ... What does the bounce message say? ... it is returned to the sender (assuming there is ... message rejected - messages from the sender or the sender's ISP are ... than the ISP they are currently dialed into (an incorrect setting in the mail program). ...
    (microsoft.public.windows.inetexplorer.ie6_outlookexpress)
  • Re: [Full-Disclosure] Block notification / bounce mails (as in DDOS)
    ... Mail performance WILL be impacted, ... your ISP, zero port 25 traffic is allowed from your ISP to your site. ... Block notification / bounce mails ... > * contact my ISP and search for a decent solution ...
    (Full-Disclosure)
  • Re: VIRUS HELP????
    ... > Purl Gurl wrote: ... Your ISP, or an ISP providing connectivity to ... spammer, before spamming occurs. ... We also discussed email spam. ...
    (alt.computer.security)