Re: How long does read(2) wait before an EAGAIN is thrown?

On Jun 23, 8:09 am, David Schwartz <dav...@xxxxxxxxxxxxx> wrote:
On Jun 20, 6:53 pm, Logan Shaw <lshaw-use...@xxxxxxxxxxxxx> wrote:

The original poster is talking about initiating a connection to an
SMTP server, so how would the code they're writing to do this be
part of the spam rejection process?

That's when the server first knows the IP address the information is
coming from. That may trigger various blacklist lookups and the like.
The idea being that if the server is known to be a pure spam source,
the connection can be dropped at the earliest point.

It may also delay/block the connection just because the IP address is
not on its approved list. The idea is to slow the sender down a bit,
drop the connection, and let the connection through later if the
sender retries in a reasonable interval. The hope is that spam sources
will not retry while legitimate mail sources will.


What do I do to act like a legitimate sender?

That is, what value does the
SMTP protocol timing have in rejecting spam if you're the sender
of the message?

I'm not sure I follow what you're saying here.

It's not clear if his code waits for the initial greeting before
sending his hello or not. I think that would generally be considered
good practice, but you don't really need to. As a result, it may be
tricky to isolate the initial greeting delay from the hello response
delay.

I'm connecting to the Exim SMTP server on my local Linux box, and let
Exim send a message to an free email account on hotmail.com. That
email account never receives the messages. How can I make the messages
reach those free email accounts?

$ ./smtp-client.out lijh@uit-sz-lijh-2 uit-sz-lijh-2 25
lovecreatesbea...@xxxxxxxxxxx "SMTP example" "hello world from code"
"`date`"
220 uit-sz-lijh-2 ESMTP Exim 4.63 Mon, 23 Jun 2008 15:16:49 +0800
HELO uit-sz-lijh-2
250 uit-sz-lijh-2 Hello lijh at uit-sz-lijh-2 [192.168.3.208]
MAIL FROM:<lijh@uit-sz-lijh-2>
250 OK
RCPT TO:<lovecreatesbea...@xxxxxxxxxxx>
250 Accepted
DATA
354 Enter message, ending with "." on a line by itself
Subject: SMTP example
From: lijh@uit-sz-lijh-2
To: lovecreatesbea...@xxxxxxxxxxx
Date: Mon Jun 23 15:16:48 CST 2008
hello world from code
250 OK id=1KAgID-0004V3-SG
QUIT
221 uit-sz-lijh-2 closing connection
$
.

Relevant Pages

  • Re: How do I stop my email address from displaying in the "from" f
    ... Oh my goodness--I don't want to send spam, I want to protect my privacy so ... I will try to find the "from" header and type ... It is data that the sender composed and that the sender submitted ... > within the DATA command to the SMTP server as part of their message. ...
    (microsoft.public.outlook.general)
  • Re: OT: writing resumes with VT100 for a Lisp job
    ... >> have more connection active at the same time. ... > which would slow down the spam source a lot without wasting much time ... > of the victim server at all, thus would be suitable for large servers: ... > first, second, etc. So the sender tries the first, and if it can't ...
    (comp.lang.lisp)
  • Re: Exchange Hijacked
    ... >Lot's of spammers use domains that either have no inbound SMTP server, ... find the compromised user account ... Thats a lot of spam and a lot of email addresses, ... > Turn off the ability for authenticated users to realy and see what ...
    (microsoft.public.exchange.admin)
  • Re: SMTP not relaying all emails
    ... The emails are flagged due to having the SMTP Server in another domain, ... If it is spam blocked, the receiver can set it so it allows the GoDaddy ... ADODB.Fields oFields; ...
    (microsoft.public.dotnet.framework.aspnet)
  • Re: UOL Anti spam is back, again...
    ... smtp server. ... you gain conformity with RFC's by rejecting it whereas ... obviously rejecting when using fetchmail is a pointless option. ... waste a second of time greylisting it, scanning it for attachments, spam ...
    (Fedora)
Loading