During the hard exercise to recruit an IT Pros, you are obliged to ask questions, here are links to some Q&A:

http://www.techiebird.com/sendmail.html

https://www.brentozar.com/archive/2009/07/top-10-interview-questions-for-windows-sysadmins/

http://www.01world.in/p/windows.html

http://resources.intenseschool.com/top-interview-questions-for-system-administrators-microsoft/

https://www.toptal.com/sql/interview-questions

https://dwbi.org/database/sql/72-top-20-sql-interview-questions-with-answers

http://www.indiabix.com/technical/sql-server-common-questions/

https://www.linux.com/blog/10-job-interview-questions-linux-system-administrators

http://computernetworkingnotes.com/rhce-interview-questions/linux-interview-questions-for-experienced.html