Lesson 4 Flashcards

(86 cards)

1
Q

What makes enterprise distros of linux unique?

A

Much slower release cycles, older release of the linux kernel that are known to be stable.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some cons to enterprise linux distros?

A

They may lack support for the latest hardware

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are Redhat and Ubuntu’s support lifespane?

A

10 years
5 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some BSD based OS’s

A

FreeBSD, NetBSD, OpenBSD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is macOS based on?

A

BSD Unix with Bash shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What command is used to find your kernel version?

A

uname -r

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do power supplies do?

A

They normalize power into standard voltage requirements. This allow hardware to be made that can be used anywhere in the world.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does a motherboard do?

A

Normalizes the interconnection using standardized connectors and form factors to bring all the components of the computer together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What type of software do motherboard sometimes have on board?

A

Firmware to deal with motherboard specific hardware

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Give an example of a motherboard firmware

A

BIOS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the BIOS responsible for?

A

Configuration but also identifying, loading, and transferring control to the operating system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What standard did intel define motherboard standards?

A

EFI - extensible firmware interface

UEFI - Unified extensible firmware interface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What command can be used to see free memory?

A

free -m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the distinction between CPU and Processor?

A

A processor may hold more logic units than JUST the cpu, like a built in GPU for example

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What command can you run to see information about your processor?

A

lscpu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the max size of memory that can be accessed on a 32 bit system?

A

4gb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is HTT?

A

Hyper-Threading Technology Allows a single CPU to concurrently process multiple instructions thus virtually acting as multiple physical CPUs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are modern connection standards for storage devices?

A

SATA or SCSI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is partitioning?

A

Tells Linux if it should see the entire devices as one contiguous block of memory or if it is broken up into pieces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What would you expect the name of the device in /dev to be for the partition 3 of the third SATA drive?

A

sdc3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does the lsblk -f command do?

A

Lists the drives and their partitions with the -f it also shows the file system format/type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where are binary files stored?

A

/bin
/sbin
/usr/bin
/usr/local/bin
/usr/local/sbin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where are configuration files stored?

A

/etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are some common files found in /etc

A

group
hostname
hosts
passwds
.conf files
profile
bash.bashrc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are some common .config files in $HOME
.bashrc .profile .bash_history
26
Where is the kernel stored?
/boot
27
What is the PID that the kernel first runs after it's loaded into memory?
1 or systemd
28
What is the /proc directory?
It's a list of files and directories stored in memory, it's not written to disk. contains info about running processes, kernel config, system hardware
29
What is the /proc/sys directory?
Includes kernel configuration settings
30
What is the /dev directory?
Devices directory for all connected hardware devices
31
What is a block devices?
Devices where data is read or written
32
What is a character device?
Are those in which data is read and written in sequential order one character at a time (keyboards, text consoles, serial ports)
33
What is /dev/zero?
Provides as many null characters as requested from it
34
What is /dev/urandom?
Generates pseudo-random numbers
35
Explain the versioning in the following: vmlinuz-4.15.0-50-generic
4 = Kernel Version 15 = Major revision 0 = Minor revision 50 = Patch number
36
What command would you use to list all hard drives and partitions in /dev?
ls /dev/sd*
37
What does ps command do?
Lists the processes associated with the current shell
38
what does ps -uf do?
shows the relationship between parent and child processes
39
what does ps -v do?
Show the amount of memory usage associated with the current shell processes
40
what does uptime do?
Shows system uptime but also gives metrics on load averages
41
where are logs stored?
/var/log
42
what is the syslog daemon?
Manages system messages. it collects messages from services and programs and stores them in log files in /var/log
43
what does last do?
displays information about logins and reboots
44
what does logrotate do?
implements log rotation or cycling which means moving files, archiving/compressing, or emailing to sysadmin
45
what is the kernel ring buffer?
Fixed size data structure that records kernel boot messages as well as live kernel messages. It's purpose is to log all kernel messages produced on boot
46
what is journald?
It is the standard logging component of the OS
47
what does journalctl utility do?
reads logs because they are in binary format
48
What virtual directory of /proc should you visit to see data that top is using?
/proc/887
49
What command is used to read /var/log/wtmp
last
50
What command is used to read /var/log/btmp
lastb
51
What command is used to read /run/log/journal/id/system.journal
journalctl
52
what does dmesg do?
prints the kernel ring buffer
53
What did systemd replace?
System V in all distros
54
What command to find out when last reboot was?
last
55
which hard disks are installed (kern.log)
less /var/log/kern.log
56
When last login occured (auth.log)
less /var/log/auth.log
57
what two command can you use to view the kernel ring buffer?
dmesg and journalctl -k
58
how can you use journalctl to query ssh?
journalctl -u ssh.service
59
In top, how can you kill a process?
by pressing k followed by the pid
60
What does the Link layer handle?
Communication directly between connected devices
61
What does the network layer handle?
Handles routing outside of individual networks with addressing (IP)
62
What does the application layer do?
Enables individual programs to talk to each other
63
What addressing is using on the Link Layer?
Mac
64
What does ip link show do?
Displays a list of all available network interfaces and their link layer addresses
65
What is CIDR notation?
Used to specify how many bits are set in the subnet mask
66
What are the private IP address schemas?
10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
67
what does ip route show do?
shows the routes associated with link layers
68
What do routing tables do?
They hold a mapping of link layer mac addresses with IP addresses
69
How many groups do IPv6 addresses have?
8 groups of 4 hex digits
70
What are the three major prefix types in ipv6?
Global Unique Address Unique Local Address Link Local Address
71
What is the Neighbor Discovery Protocol?
Allows devices to find eachother and request information regarding a network they share
72
Where is DNS data stored?
/etc/resolv.conf
73
What is in the /etc/hosts file?
Checks to see if there is an address for a specific IP listed. It overrides DNS that may be at the Org or ISP level
74
what does the host command do?
Given a DNS name ig ives back IP address information
75
What does the dig command do?
Provides a more detailed version of host including DNS record types
76
What is a socket?
Communication endpoint for two programs talking to each other. Think web browser and web server
77
Name the three types of sockets
Unix socket UDP TCP
78
what does the ss command do?
Used to investigate all sockets
79
What commands would you use to assign IP addresses to an interface?
sudo ip addr add address dev interfacename
80
What does an entry in a host file look like?
ipaddress websitename
81
DNS Record type for textual data
TXT
82
DNS Type for reverse IP Address Lookup
PTR
83
DNS Type for a domain that has no address of its own and relies on another domain for this information
cname
84
DNS Type for a mail server
MX
85
What does bridging do?
Connects multiple network interfaces. Allowing all devices to communicate as if they were on the same link layer network
86
which ss command is used to see UDP sockets?
ss -u