Phillip,
After reading your response, and re-reading my post, I would like to modify
my suggestion a little, and hopefully explain it a little better.
I am using version 3 right now, but will be moving to version 4 soon I hope.
I understand that version 3 is closed, and am not asking for it to be
changed. This is only a suggestion for version 4 sometime in the future.
In my current configuration, let's say that I have a server 100.100.100.100
that does not have a reverse DNS entry available for it. BUT my client
demands that I accept any email that this client sends to them.
To receive email from this server, I have to make the following entries:
host_lookup = !100.100.100.100:*
host_reject_recipients =
!100.100.100.100:*.somesite.com:*junkmail.com:.......
sender_unqualified_hosts =
100.100.100.100:another.site.com:mail.somewhere.com:......
(and any other places that may have host names in the tables)
(Placing the exclusion only in host_lookup, will still cause the email to be
rejected from by the host_reject_recipients section unless you add the
exclusion there too.)
I think it would be easier if we just had an entry like:
host_lookup_exclude = 100.100.100.100
-- OR --
if host_lookup has the !100.100.100.100 in it, then stop ALL failures caused
by attempts to do a reverse-dns lookup.
In my case, I added !100.100.100.100 to my host_lookup section, and assumed
that the reverse-dns error would be fixed. The bad side of this was that it
took me another 3-4 hours to discover why their email was still being
rejected, the good side, was I was forced to learn more about how exim
works.
The right answer, of course, would be to force everyone to set up
reverse-dns, but in our world of "supply and demand" (pronounced, "if you
don't do it, we will hire someone that will") we can't always have what we
want.
Finally, if my suggestion doesn't apply to exim 4, count this one up as
ramblings from a crazy-over-worked administrator, and ignore it. I will try
to move to 4 as soon as time allows.
Thanks
Terry.
-----Original Message-----
From: exim-users-admin@??? [
mailto:exim-users-admin@exim.org]On
Behalf Of Philip Hazel
Sent: Friday, March 22, 2002 10:53 AM
To: Terry Shows
Cc: exim-users@???
Subject: Re: [Exim] Reverse DNS Lookups
On Fri, 22 Mar 2002, Terry Shows wrote:
> I guess this is a feature request.
>
> Currently, if you use domain names in host_reject,
sender_unqualified_hosts,
host_reject is an Exim 3 option. I assume you are talking about Exim 3.
I'm afraid that feature requests for Exim 3 are closed.
However, reverse lookups do still happen in Exim 4. :-)
> I understand that if you don't use any domain names in your host tables,
> then the reverse dns lookup can be turned off easily, but in my case, I
want
> to be able to include some wildcard host entries in some of my tables.
I don't understand what you want. You have something like *.x.y.z in a
host list, but you want to say "if the IP address is 1.2.3.4, don't
look it up in order to see if the host matches *.x.y.z". Is that right?
If so, what do you want to happen? Should 1.2.3.4 be "in" the list, or
"not in" the list?
You can, of course, configure whether it is in or out by putting the IP
address in the list. But you want to avoid doing this in lots of
places... but you may want it to be in some lists and not in others, so
I can't see that any kind of global request is going to help.
In Exim 4, all this control is done in a different way, in access
control lists. It is often possible to avoid listing things more than
once, but it does of course depend on exactly what you are trying to
achieve.
Also note that the "reverse lookup" in fact uses gethostbyname(), so you
can, if you want, put these addresses into /etc/hosts, and get round the
problem that way.
I think I am asking: What is the *real* problem? :-)
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
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