Re: [exim] Deny vs. Drop

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Author: Renaud Allard
Date:  
To: exim-users
Subject: Re: [exim] Deny vs. Drop

>From RFC2821:


---------
An SMTP server MUST NOT intentionally close the connection except:

- After receiving a QUIT command and responding with a 221 reply.

   -  After detecting the need to shut down the SMTP service and
      returning a 421 response code.  This response code can be issued
      after the server receives any command or, if necessary,
      asynchronously from command receipt (on the assumption that the
      client will receive it after the next command is issued).
----------


So you are basically breaking RFC by dropping connection.
That does not mean I don't do it on my server, but you should be certain
you have a spammer or spambot in front of you. Some MTA don't reports
correct error messages when the connection drops, so this may be an
issue if you drop a valid message, because the sender may not be warned
the way he should.

Other than that, you are totally right, dropping connections spares the
memory and CPU time.

> Subject:
> [exim] Deny vs. Drop
> From:
> Marc Perkel <marc@???>
> Date:
> Fri, 05 May 2006 15:07:59 -0700
> To:
> exim-users@???
>
> So - if I'm denying a connection then why shouldn't I just drop the
> connection? Dropping the connection will reduce the number of open
> connections and not count on the sender to close the connection.
>
>What am I missing?