Feature request: ability to set TTL for negative DNS replies (empty result or NXDOMAIN) in a separate way

[alpominth]

Let's suppose I configured smartDNS for caching results for 7 days and a site I use to visit expires its domain registration.

/\ The negative response (NXDOMAIN) could be cached, if the site returns in 2 or 3 days, I will notice that the site is back only after 7 days as the cached negative answer would tell that.

An option to set a TTL for empty results or NXDOMAIN would be useful in this scenario.