单项选择题 Auserwiththeuseridof’joe’isunabletorshfromSYSTEMAtoSYSTEMBwithouthavingtoretypetheirpassword，buttheycanrshfromSYSTEMBtoSYSTEMA.Nootherusersareexperiencingthesameissue.Bothsystemshavea/home/joe/.rhostsfilethatcontaintheproperreferencestotheotherhost.The/home/joe/.rhostsfilesonbothSYSTEMAandSYSTEMBareownedbyuserid’joe’.Whichofthefollowingisthemostlikelycauseofthisproblem？（）

单项选择题 AsystemadministratorwantstocoupletwoserverstogethersothatusersfromserverAcanaccessserverBwithoutenteringtheirpassword.Howwouldthisbeaccomplished？（）

单项选择题 Thefollowingentryisinthe/etc/host.equivand/home/jsmith/.rhostsfileonserverAlpha：+jsmith.Whatdoesthisentryindicate？（）