If an attempt to populate &$sender_host_name$& has been made
(by reference, &%hosts_lookup%& or
otherwise) then this boolean will have been set true if, and only if, the
If an attempt to populate &$sender_host_name$& has been made
(by reference, &%hosts_lookup%& or
otherwise) then this boolean will have been set true if, and only if, the
other times, this variable is false.
It is likely that you will need to coerce DNSSEC support on in the resolver
other times, this variable is false.
It is likely that you will need to coerce DNSSEC support on in the resolver
Exim does not perform DNSSEC validation itself, instead leaving that to a
validating resolver (eg, unbound, or bind with suitable configuration).
Exim does not perform DNSSEC validation itself, instead leaving that to a
validating resolver (eg, unbound, or bind with suitable configuration).
If you have changed &%host_lookup_order%& so that &`bydns`& is not the first
mechanism in the list, then this variable will be false.
If you have changed &%host_lookup_order%& so that &`bydns`& is not the first
mechanism in the list, then this variable will be false.