On Fri, 5 Dec 2003, Tim Jackson wrote:
> I agree entirely, with one crucial exception: the *administrator*. In this
> context, I think it *is* meaningful to want to deliver mail to a specific
> box, if one knows that it is running an MTA. (And if it isn't, the mail
> bounces - no problem).
Why? Can you really assume that deliving to a specific box is going to
get to the (logical) person you are trying to contact? Doesn't the
administrator of the box have a say in this? You may (think you) want to
deliver mail to my box; as administrator I may not want you to do this
unless you use a properly constituted domain address. One cannot lay
down any kind of "law" here.
Meta-point to this argument: Exim has been the way it is now for a looong
time. It would take a huge amount of persuading to convince me to make a
change to the default, because such a change has the chance of doing the
wrong thing to all the existing users who upgrade.
> Bear in mind, however, that you, presumably, have your machines configured
> properly :) The usual case of wanting to contact a postmaster at a
> particular machine is because it's got some configuration problem.
So what makes you think it will be correctly configured to accept mail
to postmaster@[ip.address] then? :-) Surely you will do better to find
an appropriate domain and use that; it might go to a correctly
configured machine and actually get to somebody.
> 1. (main problem): It's not systematic. As Tom pointed out, DNSBL's that
> have automated systems for checking/adding/removing open SMTP relays are
> an example of why you might want to be able to contact the administrator
> of a specific machine systematically (DSBL is one I know about).
I'm sorry, I just don't believe this is generally desirable or possible.
As it happens, we haven't blocked port 25 access to the machine I'm
currently using at the border routers, but we might well do so. There
are plenty of similar configurations where outgoing mail servers send
out mail to the world but won't accept incoming mail connections from
outside their borders. And what about people using NAT and load-sharing
hardware and stuff like that? One IP address may well not correspond to
one box.
> Do you see what I'm getting at?
I see your argument. I just don't happen to agree that the facility will
be useful as often as you claim.
I may be biased, but at least I have provided the feature for those that
do agree with you. However, as I said above, I'm very against changing
the default, for compatibility reasons.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book: http://www.uit.co.uk/exim-book
