Re: Postfix policy servers

On 2004-08-01 Peter Bowyer <[email protected]> wrote:
> Andreas Metzler <[email protected]> wrote:
[...]
> > So you either have to modify the policy servers or ask Phil to enhance
> > $readsocket to add an option forcing it to close the connection. I do
> > not think this should go into exiscan, but into exim proper.

> Interesting - I'm not sure I agree, though. Exiscan has developed into a way
> of hiding the complexity of communicating with various third-party policy
> engines, providing a consistent high-level interface to the Exim config file
> with no complex socket handling needed from Exim. I'd say this fits very
> well with that paradigm.

> Maybe advanced users might want to call a Postfix policy server directly
> from their Exim config code, and it would be useful for the core product to
> support that. But for the general-purpose drop-in user, Exiscan does the job
> better IMHO. Look at how easy it is to drop in AV scanning with ClamAV or
> Sophie.. nothing to tweak except high-level config items such as
> host/port/socket etc.

The difference is that you could not do that easily in pure exim
without
a) ugliness
b) sideffects. You'd nee to at least set message_body_visible to a
big value.

And I think even if you accepted a and b it would not be possible.

OTOH these policy daemons are /almost/ a _perfect_ match for exim's
built in capabilities:

defer condition = ${if match \
{${readsocket{/path/to/socket}{request=smtpd_access_policy\nsender=$sender_address\nrecipient=$local_part@$domain\nclient_address=$sender_host_address\n\n}}}\
{DEFER_IF_PERMIT}{true}{false}}

A exiscan wrapper could only simplify this marginally, unless it
limited itself to a subset of the policy-daemon featureset. IMHO.
                       cu andreas
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