Regardins DNSSEC: https://en.wikipedia.org/wiki/Domain_Name_System_Security_Extensions
Since version 2018.11.2.0 we’ve added a DNS option tab to the SFTP Source and Destination Setup. This option let’s you override the system DNS. Reason that we’ve added this is security (suppose your system got hacked). This option let’s you firmly control the DNS requests. We’ve also added an option to use DNSSEC (“Use Security”). This is all new for us so feedback is more than welcome.