Re: [Exim] 451-Invalid HELO

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著者: Andy Saunders
日付:  
To: exim-users
題目: Re: [Exim] 451-Invalid HELO
On Thu, 29 Apr 2004 at 12:14 +0100, Alan J. Flavell wrote:
> It sort-of gives the site an opportunity to fix the problem, doesn't
> it?


That was the reasoning behind choosing 'defer'. Malware will probably
not retry, and legitimate senders have a chance to fix their server in
order to get their mail through.

The acl has been live for around 8 weeks and rejects over one million
recipients per week. During this time, only two senders (that I know
of) have had trouble, and in both cases the sender has fixed his/her
server. Two trouble tickets against 8 million worms/spams seems a fair
trade to me.

The rcpt_to acl (which is run after mail to postmaster is accepted) is
nothing more than a simple syntax check

defer   message = Invalid HELO ($sender_helo_name) used by $sender_host_address. \
                  See RFC2821 S4.1.1.1 for syntax of the HELO command. \
                  This is a temporary error.  You may try again after this \
                  server ($sender_host_address) has been fixed.
        condition = ${if match{$sender_helo_name}{\N^[^.].*\.[^.]+$\N}{no}{yes}}
        log_message = $sender_host_address gave an invalid HELO of $sender_helo_name



--
Andy Saunders
Oxford University Computing Services