Had the same problem before Zesty and used some of the fixes described here to have postfix restart through rc.local file after waiting a few minutes. The bug is still persistent for me after upgrading to Zesty. What does fix it for me though is adding the "After" line to the Unit: /lib/systemd/system/postfix@.service
After=network-online.target Note: it did not work to make this change to the postfix.service unit. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1519331 Title: Postfix cannot resolve DNS if network was unavailable when it was started, such as on a laptop To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/postfix/+bug/1519331/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
