Take note: Create a file under /etc/apt/resources.record.d, not the /etc/apt/resources.listing file in which the distribution's official repository addresses are located. This can be a system that won't destabilize your program. It is recommended. We use DNSSEC validation when possible, as which allows us to be sure the responses are https://wise-social.com/story2389241/5-simple-statements-about-linux-postfix-mail-server-setup-explained