Re: [Fwd: Re: Malayalam GNOME Translation]

[Åsmund Skjæveland <asmund skjaveland usit uio no>]

On Wed, Jul 12, 2006 at 11:58:49AM +0100, Simos Xenitellis wrote:
> ???????? 12-07-2006, ?????????? ??????, ?????? ?????? 09:39 +0530, ??/?? Ani Peter ????????????:
> > Hi,
> > 
> > I am trying to send this message since yesterday, but its bouncing. Do 
> > not know what is the reason..trying once again..
> 
> The mail server (mail.gnome.org) appears to be receiving too many spam
> connections lately that can cause it to miss legitimate connections from
> your mail server (that is, your mail server may try a few times to
> connect to mail.gnome.org but they all happen to fail).

My university uses a simple and apparently very effective anti-spam trick:

When an SMTP connection from an unknown/external host comes in, the
connection is accepted, and the remote machine then sends HELO or
EHLO. The local server then does nothing, but simply holds the
connection for thirty seconds before answering. If I understand
correctly, this is well within the required limits of an SMTP
conversation, but a spammer, which has to go thru thousands or
millions of such conversations (and perhaps operates from a pwned
private computer) will usually just send the message without listening
to what the SMTP server answers. Since the SMTP server has not yet
answered the HELO/EHLO, it ignores everything the remote host says.

-- 
Åsmund Skjæveland {
	kaffi();
}