单项选择题
A.en0 has no associated ip address.
B.serverB is missing its default route.
C.serverB and serverA cannot connect due to a firewall.
D.en0 has been set up to block traffic from servers that are in different subnets.
单项选择题 The ping loopback hangs with no output. Which of the following is the most likely cause？（）
单项选择题 An administrator has set up serverA and serverB to use the /etc/hosts.equiv file so that applications on serverA can remotely run commands on serverB. Which command will verify if a new user from serverA is trusted on serverB？（）
单项选择题 A system is experiencing packet routing problems，when the administrator runs ’netstat -nr’ the following default routes are displayed： default165.253.251.1UG51601304 en8-- default192.168.50.1UGH01590450 en4-- Assuming the first route is correct，how can the administrator remove the incorrect default route？（）