On Friday, September 02, 2011 04:49:14 AM [email protected] 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
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Phone +1 951 643-5345, or see: http://www.nobaloney.net/contactus.html
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