help with the control.

[evgen-20058]

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[Kerms]

That vaguely looks like some basic linux sysadmin test issued by some college.
Are you asking for help on it?

1. Group these IP addresses by network:
192.168.6.1 (255.255.255.224)
192.168.6.24 (255.255.255.224)
192.168.6.31 (255.255.255.224)
192.168.6.33 (255.255.255.224)
192.168.6.55 (255.255.255.224)
192.168.6.61 (255.255.255.224)
192.168.6.63 (255.255.255.224)
192.168.6.64 (255.255.255.224)
192.168.6.65 (255.255.255.224)
192.168.6.75 (255.255.255.224)
192.168.6.76 (255.255.255.224)

What does `by network' mean? You gave 10 local IPs with what seems to be a netmask, and some of the IPs are illegal from the netmask rules. (Allowed 192.168.6.1 - 192.168.6.30)

2. Fill in the port numbers that come to mind when you see below service names (Hope you don’t have to Google; If you used Google – Mark it so)

http 80, 8080
ftp 21,20
telnet 23
pop3 110
https 443
dns 53
snmp 161
smtp 25
tcp здесь я не понял что имелось в виду
ssh 22

3. Fill in the service names that come to mind when you see these ports (Hope you don’t have to Google; If you used Google – Mark it so)

tcp port 110 pop3
tcp port 3389 rdp
tcp port 2689 -
tcp port 139 netBios
tcp port 389 ldap
udp port 53 dns
udp port 123 ntp
udp port 500 isakmp
udp port 514 shell, syslog
tcp port 666 -
tcp port 3128 kerio firewall

http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

4. If a pc has a DHCP lease of one day, how long (in minutes) after obtaining that lease will this workstation attempt to renew it?
720 min

720 minutes is 12 hours; 12(hours) * 60(minutes) = 720(minutes); 1440 minutes is 24 hours.

5. If a pc has a BOOTP address, how long (in minutes) after obtaining that address will this workstation attempt to renew it?
By default, the BOOTP protocol allocates a dynamic IP-addresses to rent for 30 days.

You answered in days; for the time, it's correct, but the question was asking for minutes.
30(days) * 60(hours) * 60(minutes) = 108000(Minutes)

7. If a Computer’s IP address is 192.168.7.62 and its default gateway is 192.168.7.33, which of the following could not possibly be the pc’s netmask?

255.255.255.128 no
255.255.255.192 only
255.255.255.224 no
255.255.255.240 no
255.255.255.248 no

Assuming 192.168.7.62 is the highest available IP, you need a netmask that at least allocates 64 raw IPs; so the subnet can be 255.255.255.192 or less.
Therefore, 255.255.255.224, 255.255.255.240, 255.255.255.248, are illegal subnets.

8. If I wanted to find out the IP address of the host(s) that accept(s) mail on behalf of domain foo. com, what DNS record would I be interested in?
$ host foo. com

That seems correct. The command `dig' is a more verbose dns lookup tool.

9. What company owns the IP block 172.25.3.0?
$ host 172.25.3.0

Command `whois' actually does that.

10. To display a list of all manual pages containing the keyword "date", what command would you type?
$ man date;$ info date.

What you gave is the man page for the command date. What I think you want is `man -k keyword'.
If you want all manpages that contains the instance of the word `date' in the man pages' context, I'm afraid you have to create a script to do that.

11. Linux user accidentally entered cd; chmod 644 . into terminal followed by “Enter/Return” command
- What problem occurs when he/she logs in the next time, and what level of privilege is required to undo the changes?
644 – -rw-r--r-- All users have read access, the owner can edit

You need execute permissions on the directory to cd into it. Root or the owner can fix this.

This command is run as root. Defualt user can not change the attributes of files and directories.
12. Write a shell script to append "echo\n123" to the file ".ocean” but only if "sea" and “.ocean” file already exists.
[ -f sea ] && echo 123 >> .ocean

if [ -f sea ] && [ -f .ocean ]; then; echo "echo\n123" >> .ocean; fi
or
[ -f sea ] && [ -f .ocean ] && echo "echo\n123" >> .ocean
You wrote "If sea exists, append '123' to .ocean" and the question asked if both .ocean and sea exists, write.

14. How would you list 13 files / directories size wise in reverse order?
$ ls -S

ls -rS
-r Ascends (reverses) it.




Lastly, taking a class to learn Linux or to become a sysadmin is the wrong way. Yes, it's useful, it teaches you stuff, but what makes a good Linux user or sysadmin is self exploration/education.
What this class/test is teaching you is that there is only one way to do things. This is wrong. There are literally hundreds, if not thousands of ways to do what this test is asking for.
And on top of that, the test is implying that you have to remember this crap. To put it, no sysadmin/linux user will ever blame a Google-class sysadmin to search some trivial how-to or reference charts in some man page or via search engine.
Google is your best friend you will ever have; don't try to alienate him.
Hell, I even used google on more than half of these questions.

 

[evgen-20058]

You answered in days; for the time, it's correct, but the question was asking for minutes.
30(days) * 60(hours) * 60(minutes) = 108000(Minutes)

Why 60 (hours) in a day is 24 hours??
30(days) * 24(hours) * 60(minutes) = 43200(Minutes)

That seems correct. The command `dig' is a more verbose dns lookup tool.

but it is better to use $ host -t mx foo.com

ls -rS

IMHO, I would use $ du -hs * | sort -r -h | head -13

if [ -f sea ] && [ -f .ocean ]; then; echo "echo\n123" >> .ocean; fi
or
[ -f sea ] && [ -f .ocean ] && echo "echo\n123" >> .ocean

wrong, an error... would be so true
[[ -f sea && -f .ocean ]] && echo 123 >> .ocean


thank you for your help
have tried Russian forums, there are not many avail

 

[Kerms]

Why 60 (hours) in a day is 24 hours??
30(days) * 24(hours) * 60(minutes) = 43200(Minutes)

Crap, you're right. Thought typo.

wrong, an error... would be so true
[[ -f sea && -f .ocean ]] && echo 123 >> .ocean

At least on Bash, my way worked; I don't think it's an error.


Lastly,
Sadly, I don't speak Russian, and using a Translator will be a bit awkward for me.
But either way, I'd be glad to help with a few.
(Where is the Russian forums?)

 

[evgen-20058]

the only forum that helped me a linuxforum.ru
there besides my questions were still a lot of useful information that can take note.

 

[evgen-20058]

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