Unless you really know what you are doing, leave it alone.
4. If not built with DISABLE_DNSSEC, Exim now has the main option
- dns_use_dnssec; if set to 1 then Exim will initialise the resolver library
+ dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
to send the DO flag to your recursive resolver. If you have a recursive
resolver, which can set the Authenticated Data (AD) flag in results, Exim
- can now detect this.
+ can now detect this. Exim does not perform validation itself, instead
+ relying upon a trusted path to the resolver.
Current status: work-in-progress; $sender_host_dnssec variable added.