Question about quarantine

[Simon Brereton]

On 4 May 2013 12:02, "Patrick Joy" <paddy at paddyjoy.com> wrote:
>
>
> On 04/05/13 19:44, Simon Brereton wrote:
>>
>> > On 04/05/13 18:58, Simon Brereton wrote:
>> >>
>> >>
>> >> On 4 May 2013 05:15, "Patrick Joy" <paddy at paddyjoy.com> wrote:
>> >> >
>> >> > Hi everyone,
>> >> >
>> >> > I have just configured amavis-new (2.5.3) and spamassassin (3.2.5)
and integrated with postfix (2.5.1). I have linked amavis to mysql also.
>> >> >
>> >> > Everything seems to working fine, spam headers are being added and
some mail is going the the quarantine however I would appreciate it anyone
could answer the following questions about the behaviour of the quarantine.
>> >> >
>> >> > I have the following settings:
>> >> >
>> >> > $sa_spam_subject_tag = '***SPAM*** ';
>> >> > $sa_tag_level_deflt  = -9999;  # add spam info headers if at, or
above that level
>> >> > $sa_tag2_level_deflt = 8; # add 'spam detected' headers at that
level
>> >> Email will have ***SPAM*** added to the subject..
>> >>
>> >> > $sa_kill_level_deflt = 10; # triggers spam evasive actions
>> >> Email will quarantine..
>> >>
>> >> > $sa_dsn_cutoff_level = 15;   # spam level beyond which a DSN is not
sent
>> >>
>> >> Email will be discarded. Sender will not be notified.  See
$final_spam_destiny       = D_DISCARD;
>> >>
>> >> > $final_virus_destiny      = D_DISCARD;  # (data not lost, see virus
quarantine)
>> >> > $final_banned_destiny     = D_BOUNCE;   # D_REJECT when front-end
MTA
>> >> > $final_spam_destiny       = D_DISCARD;
>> >> > $final_bad_header_destiny = D_PASS;     # False-positive prone (for
spam)
>> >> >
>> >> > 1) Does this mean that anything with a score over 8 will go the
quarantine?
>> >> > 2) What happens emails with a score over 10? Do they get discarded
or do they go to the quarantine?
>> >> > 3) What happens emails with a score over 15? Do they get discarded
or do they go to the quarantine?
>> >> >
>> >> > My aim is to have nothing discarded, I would like all suspected
emails to go to the quarantine and have users decide before whether they
get discarded or not. Do I have the correct settings for that?
>>
>> On 4 May 2013 11:31, "Patrick Joy" <paddy at paddyjoy.com> wrote:
>> >
>> > Thanks Simon,
>> >
>> > So if I don't want anything to be discarded I should increase
$sa_dsn_cutoff_level to something large like 9999?
>>
>> Please don't top post..
>>
>> Yes, or I believe just comment the line out.
>
> Thanks I'll experiment with both.
>
>> For what it's worth I've never seen a legitimate mail with a
spamassassin score over 15.  I can't imagine why you'd want to not discard
them.
>
> That's good to know! The main reason I want to keep them all is because
customers can be funny sometimes, one missing email (legitimate or not) and
they will be up in arms.

But it's your responsibility as a service provider (which if you have
customers is what you are) to also protect them.  And us.  And you.

Assume I'm wrong and only most email 15 and over is spam... the ones you're
quarantining for them to look at contain phishing links and
viruses/Trojans, whether by payload or link.  Now if your customer is not
educated to appreciate that smtp is an unreliable communications protocol,
they are probably also likely to click on Trojan installers and respond to
phishing attacks.

Now their network is compromised, or your machine is spewing spam and in a
blacklist.   Now all your other customers are mad and you have much bigger
problems than a missing email (which might have gone missing for any number
of reasons out of your control).

In short, yes, you have to, as a service provider, provide reliability.
But as with any it service you have to balance the wants of a few against
the security of many.

It's of course your machine, your customer and most important of all, your
policy.  I'm not mandating what you should or should not do, but have a
think about it and the implications and look at the risk/reward.

Good luck!

Simon
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