Re: [exim-dev] Bug: No warning or default for missing retry …

On Wed, 2007-06-20 at 17:10 +0100, Philip Hazel wrote:
> There *is* a retry section in the default Exim config.

...which is present in almost all of the packaged versions of Exim I've
come across, unaltered.

> > If this section is missing no warning or error is logged
>
> If you remove the section, it is assumed you want no retries.
>
> > I suggest to add a warning to the panic log and/or a default retry
> > setup.
>
> I am not sure this is right, but what do others think?

I agree with Philip. There are several sections of the Exim config which
it is possible to remove and still have a fully functioning system.

Consider ACLs - the documentation describes a complete ACL section which
only has three lines (see Ch.40). It is possible to remove all the
defaults and replace them with:

acl_smtp_rcpt = do_not_use_this_acl

begin acl
do_not_use_this_acl:
accept

Success using that will depend on config in the routers, but it
illustrates the idea.

You could also completely remove the authenticators and rewrites, and
all the routers except dnslookup, and all the transports except
remote_smtp and *still* have a functioning system - crippled, but
technically functioning.

I can think of a number of situations where it's quite possible no
retries at all would want to be done - think time-critical delivery such
as for alarm systems (although using SMTP for alarm propagation is a bad
idea, I know of several fire alarm systems that use it!).

Perhaps the docs need to be amended to state categorically that:

Removal (or omission) of the retry section, or inclusion of the section
with no rules, results in there being no retry attempts on any sort of
error condition. All errors will, therefore, immediately be treated as
permanent.

Graeme