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From Charles Benett <char...@benett1.demon.co.uk>
Subject Re: SMTP RFCs
Date Wed, 07 Aug 2002 15:13:06 GMT
Philipp Taprogge wrote:
> Hi!
> Thomas Jachmann wrote:
>> I know that this
>> behavior is wanted since one main goal is making james as configurable as
>> possible, so everything was handled within the spool via 
>> matchers/mailets.
>> But james would still be that configurable if you'd have two 'spools' -
>> matchers/denyers and matchers/mailets.
> What Thomas said about DOS attacks is a good point. Besides even if a 
> james server is not subject to a DOS attack, it still will produce much 
> higher bandwidth costs as it accepts all the spam messages it will later 
> discard. Especially small companies paying for their traffic by the MB 
> will find this an issue.
> Another question that arises is: do we really need this much flexibility 
> at this early point of mail processing? If we merely check the FROM: and 
> TO: fields of the mail or maybe one or two other parameters, wouldn't 
> that be enough to determine whether to accept the message or not?
> You can still have mailets to discard messages based on a much more 
> fine-grained basis, perhaps if a message contains certain phrases and such.
> But when a message is denied because of policy ("we do not relay"), the 
> client should be notified immediately

FROM and TO can be forged so you would get false negatives using those. 
(Ie emails not rejected when they should have been)

> One other point that came to my mind...
> I will have a look at the code later, but perhaps one of you could 
> enlighten me in the mean time:
> what exactly happens when james can not process an incoming mail because 
> of an internal error?
> Is there a mechanism to send the client a 550 response or will james 
> accept the message with a 200 and then fail to process it?

If the error is encountered by the SMTPServer you should get a 550. But 
if its encountered by the MailetEngine then what happens depends on how 
you have configured your mailets, but it won't be a 220 (as the SMTP 
sessin has closed). It might get sent to the Error mailbox, the 
postmaster os sender might be notified. Depends on configuration.

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