单项选择题 Asystemadministratoristryingtotroubleshootcompanywideemailproblemsthatmayberelated toDNS.WhichofthefollowingnetworktoolswouldbeMOSTusefultodetermineifitisaDNS issue？（）

单项选择题 Theserverroomthatanadministratormanageshasjustcaughtfire.Whichofthefollowingisthe FIRSTthingthattheadministratorshoulddo？（）

单项选择题 A user cannot access files on /deps/it directory, the administrator verifies permissions are set for the directory. Which of the following actions need to be performed to only grant read access to the user on the IT directory?（）