On Fri, 20 Sep 2002, Nico Erfurth wrote:
> 1.) Very simple approach, just add
> host_reject_connection = +include_unknown
That will have no effect because "+include_unknown" applies to the
testing of any following item in the list. As there are no following
items in the list, Exim won't need to test anything, so +include_unknown
won't do anything. You would need to force it by something like
host_reject_connection = +include_unknown : non.existent.domain
Then Exim would try to look up the host name in order to test against
"non.existent.domain".
> 2.) the ACL way, exim provides us with
> <quote>
> $host_lookup_failed: This variable contains ``1'' if the message came
> from a remote host and there was an attempt to look up the host's name
> from its IP address, but the attempt failed. Otherwise the value of the
> variable is ``0''.
> </quote>
There's a catch there too. You have to make sure that Exim does attempt
a host lookup. You can do this by setting
host_lookup = *
> you could use this variable in an ACL (rcpt_acl) like this
>
> deny message = Sorry, your IP could not be looked up
> condition = $host_lookup_failed
>
> The problem with this one is that it will permanent reject when you have
> DNS-Problems.
Indeed.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
