As a new-ish user of exim I would like to make the following
comments, in the hope that they will be useful. I know that
when one is in the thick of a design, knowing it inside out,
one may forget how things look to those unfamiliar with it, so I
am hoping this perspective may be of help. I don't wish to imply
that new users have been forgotten, there is the overview document
and other information in the FAQs and Specification of course. I'm
putting this to the list so others can tear down or enhance these
suggestions.
(I was on the list a good while back, but didn't setup exim because 1.9
didn't do all the domain hiding that I wanted to do. It turns out
that 3.02 will do it, but the other admins here don't want it done! :-) )
Firstly, I should say that I am very pleased with Exim and how
clear the design and the configuration file are. Once I had
written the configuration file and changed it a few times, I could read
it and see what was happening. I was using sendmail before,
so I won't bother to compare the experiences :-) The diagnostic
messages from exim are useful and generally very clear, too.
Secondly, the documentation is very good, and I can see a lot
of work has gone into such a monster manual.
Thirdly, the on-line support is just terrific.
However, there were a few things that I think could be made clearer.
Directors, routers, drivers: I kept getting mixed up with these.
I have it straight now. While mixed up, I found it hard to visualise
the flow of control in the configuration file, and it took a while
to "click" that $local_domains determined which path a message took
through the drivers. May I suggest a (simplified) diagram near the
start of the Postscript document, as this would stand out visually
for easy reference? I have to say that I never really got this flow
clear in my mind with sendmail. I also see that the order in the
file is (partly) due to "define before use": the transports must
come before the drivers, etc.
It took me a while to find that mail regarded as local (because of
name rewriting) which actually wasn't, could be kicked out of the
local path with a smartuser director. Maybe when directors and
routers are first explained, how to get from one to the other could
be mentioned in such a way that one knows what to lookup easily?
Where variables interact with one another it may be useful to supplement
the descriptions with a table, showing what happens when each is
set/true/false/unset.
relay_domains, host_accept_relay: I feel it may be clearer if
these were called incoming_relay_destinations and outgoing_relay_sources
or something of the sort, so the distinction is more explicit.
My relaying problem was the only case where I could not tell from
the error message what was wrong: the host was not accepted for relay
but I could not tell why it had failed. Thank you, Philip, for
helping me out with that.
Examples of syntax: There are quite a few of these, but some more
would be nice, near to where they are needed. For example, while
re-organising my host lists to be on folded lines I had to jump about
the docs to find how to get the syntax, including those of regexps
(doubled backslashes) right. The documentation says you can use
regular expressions to match hostnames, but I could not find anything
explicit about using them for IP address specs, so I didn't do that.
The structure of the documentation: This is good, particularly for
understanding the structure of Exim. Where I feel it could be improved
is when one is in troubleshooting mode. May I suggest that there
be a troubleshooting section with common mistakes at the end of each
chapter, so that when things go wrong one can find the solution more
quickly? I know it is really a specification document, but I think
it serves more than that function. With the troubleshooting parts in
the index as well, navigation in times of panic would be simpler.
I am aware that these suggestions would make the documentation bigger,
so there would be more to maintain, so that may outweigh any advantage.
I am not a technical writer by profession, and I may well have missed
information "staring me in the face" :-), so please take these
suggestions with enough "salt".
Thank you,
Hugh
hgs@???
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