Re: [exim] delaying inbound messages

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Author: Jeff Lasman
Date:  
To: exim-users
Subject: Re: [exim] delaying inbound messages
On Friday, September 02, 2011 04:49:14 AM Lena@??? wrote:

> Exim already does that by default. Read description of the
> smtp_enforce_sync main configuration option, then telnet to Exim, you'll
> see 3 seconds delay between connection and SMTP banner. If a spambot or an
> abused proxy tries to send HELO before the banner, Exim drops the
> connection.


I just telnetted into one of my servers (they all run the same exim.conf file)
on port 25 and got an immediate reply.

I checked and there's no reference to the option in my exim.conf file.

Yet the rejection is triggered occasionally; my current rejectlog shows it 35
times in approximately 4-1/2 days. So I'm a bit confused.

> SMTP protocol synchronization error (input sent without waiting for
> greeting): rejected connection from
>
> > # Accept hosts who are polite enough to wait rather than just send, as
> > spammers do accept hosts = *
> >
> >          delay = 3s

> >
> > # Deny hosts who don't wait
> > deny message = Too quick on the draw - to unblock wait for helo/ehlo
>
> This "deny" is never reached.


I can't test this because I don't use it; I'll check with the gent who
submitted it to me, and ask him. But I believe you're right, as exim is
returning it first.

Can you tell me why my own tests from my desktop on port 25 don't seem to get
delayed?

Thanks.

Jeff
--
Jeff Lasman, Nobaloney Internet Services
Post Office Box 52200, Riverside, CA 92517
Our blists address used on lists is for list email only
Phone +1 951 643-5345, or see: http://www.nobaloney.net/contactus.html