List and describe the three options you will find in the Status column of the server services menu.
What will be an ideal response?
The Status column indicates the current status of the service as follows:
• Started shows that the service is running.
• Paused means that the service is started, but is not available to users.
• A blank means that the service is halted or has not been started.
Computer Science & Information Technology
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Which of the following components is required to connect multiple servers to a SAN?
A. Router B. HBA C. RAID controller D. Fiber switch
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The process PID 395 is nginx. How could that be concluded from the output above?
Display the services currently running. a. Use the ps command to display all the programs running in the background:
[analyst@secOps ~]$ sudo ps –elf [sudo] password for analyst: F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY TIME CMD 4 S root 1 0 0 80 0 - 2250 SyS_ep Feb27 ? 00:00:00 /sbin/init 1 S root 2 0 0 80 0 - 0 kthrea Feb27 ? 00:00:00 [kthreadd] 1 S root 3 2 0 80 0 - 0 smpboo Feb27 ? 00:00:00 [ksoftirqd/0] 1 S root 5 2 0 60 -20 - 0 worker Feb27 ? 00:00:00 [kworker/0:0H] 1 S root 7 2 0 80 0 - 0 rcu_gp Feb27 ? 00:00:00 [rcu_preempt] 1 S root 8 2 0 80 0 - 0 rcu_gp Feb27 ? 00:00:00 [rcu_sched] 1 S root 9 2 0 80 0 - 0 rcu_gp Feb27 ? 00:00:00 [rcu_bh] 1 S root 10 2 0 -40 - - 0 smpboo Feb27 ? 00:00:00 [migration/0] 1 S root 11 2 0 60 -20 - 0 rescue Feb27 ? 00:00:00 [lru-add-drain] 5 S root 12 2 0 -40 - - 0 smpboo Feb27 ? 00:00:00 [watchdog/0] 1 S root 13 2 0 80 0 - 0 smpboo Feb27 ? 00:00:00 [cpuhp/0] 5 S root 14 2 0 80 0 - 0 devtmp Feb27 ? 00:00:00 [kdevtmpfs] 1 S root 15 2 0 60 -20 - 0 rescue Feb27 ? 00:00:00 [netns] 1 S root 16 2 0 80 0 - 0 watchd Feb27 ? 00:00:00 [khungtaskd] 1 S root 17 2 0 80 0 - 0 oom_re Feb27 ? 00:00:00 [oom_reaper]b. In Linux, programs can also call other programs. The ps command can also be used to display such process hierarchy. Use –ejH options to display the currently running process tree.
[analyst@secOps ~]$ sudo ps –ejH [sudo] password for analyst:c. As mentioned before, servers are essentially programs, often started by the system itself at boot time. The task performed by a server is called service. In such fashion, a web server provides web services. The netstat command is a great tool to help identify the network servers running on a computer. The power of netstat lies on its ability to display network connections. In the terminal window, type netstat.1 1 1 ? 00:00:00 systemd 167 167 167 ? 00:00:01 systemd-journal 193 193 193 ? 00:00:00 systemd-udevd 209 209 209 ? 00:00:00 rsyslogd 210 210 210 ? 00:01:41 java 212 212 212 ? 00:00:01 ovsdb-server 213 213 213 ? 00:00:00 start_pox.sh 224 213 213 ? 00:01:18 python2.7 214 214 214 ? 00:00:00 systemd-logind 216 216 216 ? 00:00:01 dbus-daemon 221 221 221 ? 00:00:05 filebeat 239 239 239 ? 00:00:05 VBoxService 287 287 287 ? 00:00:00 ovs-vswitchd 382 382 382 ? 00:00:00 dhcpcd 387 387 387 ? 00:00:00 lightdm 410 410 410 tty7 00:00:10 Xorg 460 387 387 ? 00:00:00 lightdm 492 492 492 ? 00:00:00 sh 503 492 492 ? 00:00:00 xfce4-session 513 492 492 ? 00:00:00 xfwm4 517 492 492 ? 00:00:00 Thunar 1592 492 492 ? 00:00:00 thunar-volman 519 492 492 ? 00:00:00 xfce4-panel 554 492 492 ? 00:00:00 panel-6-systray 559 492 492 ? 00:00:00 panel-2-actions 523 492 492 ? 00:00:01 xfdesktop 530 492 492 ? 00:00:00 polkit-gnome-au 395 395 395 ? 00:00:00 nginx 396 395 395 ? 00:00:00 nginx 408 384 384 ? 00:01:58 java 414 414 414 ? 00:00:00 accounts-daemon 418 418 418 ? 00:00:00 polkitd
[analyst@secOps ~]$ netstat Active Internet connections (w/o servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 localhost.localdo:48746 localhost.local:wap-wsp ESTABLISHED tcp 0 0 localhost.localdo:48748 localhost.local:wap-wsp ESTABLISHED tcp6 0 0 localhost.local:wap-wsp localhost.localdo:48748 ESTABLISHED tcp6 0 0 localhost.local:wap-wsp localhost.localdo:48746 ESTABLISHED tcp6 0 0 localhost.local:wap-wsp localhost.localdo:48744 ESTABLISHED tcp6 0 0 localhost.localdo:48744 localhost.local:wap-wsp ESTABLISHED Active UNIX domain sockets (w/o servers) Proto RefCnt Flags Type State I-Node Path unix 3 [ ] DGRAM 8472 /run/systemd/notify unix 2 [ ] DGRAM 8474 /run/systemd/ cgroups-agentd. Use netstat with the –tunap options to adjust the output of netstat. Notice that netstat allows multiple options to be grouped together under the same “- ” sign. The information for the nginx server is highlighted.
[analyst@secOps ~]$ sudo netstat -tunap [sudo] password for analyst: Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 395/nginx: master p tcp 0 0 0.0.0.0:21 0.0.0.0:* LISTEN 279/vsftpd tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 277/sshd tcp 0 0 0.0.0.0:6633 0.0.0.0:* LISTEN 257/python2.7 tcp6 0 0 :::22 :::* LISTEN 277/sshd tcp6 0 0 :::23 :::* LISTEN 1/init udp 0 0 192.168.1.15:68 0.0.0.0:* 237/systemd-networkClients will connect to a port and, using the correct protocol, request information from a server. The netstat output above displays a number of services that are currently listening on specific ports. Interesting columns are: ? The first column shows the Layer 4 protocol in use (UDP or TCP, in this case). ? The third column uses the
[analyst@secOps ~]$ sudo ps -elf | grep 395 [sudo] password for analyst: 1 S root 395 1 0 80 0 - 1829 sigsus Feb27 ? 00:00:00 nginx: master process /usr/bin/nginx -g pid /run/nginx.pid; error_log stderr; 5 S http 396 395 0 80 0 - 1866 SyS_ep Feb27 ? 00:00:00 nginx: worker process 0 S analyst 3789 1872 0 80 0 - 1190 pipe_w 14:05 pts/1 00:00:00 grep 395In the output above, the ps command is piped through the grep command to filter out only the lines containing the number 395. The result is three lines with text wrapping. The first line shows a process owned by the root user (third column), started by another process with PID 1 (fifth column), on Feb27 (twelfth column) with command /usr/bin/nginx -g pid /run/nginx.pid; error_log stderr; The second line shows a process with PID 396, owned by the http user, started by process 395, on Feb27. The third line shows a process owned by the analyst user, with PID 3789, started by a process with PID 1872, as the grep 395 command.
Computer Science & Information Technology