Lets see ;)

Net::ADNS -> http://search.cpan.org/~salva/Net-ADNS-0.03/ -> Bug #44738 for Net-ADNS: Net::ADNS segfaults using global vars

So, don't use global vars and this module won't segfault, easy to do

use strict 'vars'; to detect undeclared vars, and then use  my $adns to make $adns a lexical variable

More on scope/strict in Lexical scoping like a fox, Read this if you want to cut your development time in half! and understand that  strict itself confers no benefits; The benefits come from avoidance of the bad practices forbidden by  strict :)