E
evgen-20058
Guest
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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)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)
http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers2. 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
720 minutes is 12 hours; 12(hours) * 60(minutes) = 720(minutes); 1440 minutes is 24 hours.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
You answered in days; for the time, it's correct, but the question was asking for minutes.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.
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.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
That seems correct. The command `dig' is a more verbose dns lookup tool.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
Command `whois' actually does that.9. What company owns the IP block 172.25.3.0?
$ host 172.25.3.0
What you gave is the man page for the command date. What I think you want is `man -k keyword'.10. To display a list of all manual pages containing the keyword "date", what command would you type?
$ man date;$ info date.
You need execute permissions on the directory to cd into it. Root or the owner can fix this.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
if [ -f sea ] && [ -f .ocean ]; then; echo "echo\n123" >> .ocean; fiThis 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
ls -rS14. How would you list 13 files / directories size wise in reverse order?
$ ls -S
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)
but it is better to use $ host -t mx foo.comThat seems correct. The command `dig' is a more verbose dns lookup tool.
IMHO, I would use $ du -hs * | sort -r -h | head -13ls -rS
wrong, an error... would be so trueif [ -f sea ] && [ -f .ocean ]; then; echo "echo\n123" >> .ocean; fi
or
[ -f sea ] && [ -f .ocean ] && echo "echo\n123" >> .ocean
Crap, you're right. Thought typo.Why 60 (hours) in a day is 24 hours??
30(days) * 24(hours) * 60(minutes) = 43200(Minutes)
At least on Bash, my way worked; I don't think it's an error.wrong, an error... would be so true
[[ -f sea && -f .ocean ]] && echo 123 >> .ocean