Week 2 - Network Services

Question 1

What does a file transfer protocol do? (FTP)

Answer 1

Allows you to store huge files and transfer files from one computer to another using the internet

(instead of carrying around a flash drive or using remote copy tools)

Question 2

How is FTP similar to SSH in its use?

Answer 2

For FTP a client also has to install an FTP client to access an FTP server and install software on the server

Question 3

What is FTP primarily used for today?

Answer 3

To share web content

(like a website host provider will have an FTP connection available to easily copy files to and from your website)

Question 4

What is SFTP?

Answer 4

Secure File Transfer Protocol

Question 5

Why is FTP not the greatest option in terms of security?

Answer 5

It’s not super secure because it doesn’t handle data encryption

Question 6

What does TFTP stand for?

Answer 6

Trivial File Transfer Protocol

Question 7

How is TFTP different from FTP? (2)

Answer 7

FTP requires user authentication, TFTP doesn’t (don’t store secure files with TFTP only generic ones)

TFTP is a simpler way to transfer files than using FTP

Question 8

What’s a popular use for TFTP?

Answer 8

To host installation files

Question 9

What does PXE/Pixie Boot stand for?

Answer 9

Pre-boot execution

Question 10

What does PXE allow you to do?

Answer 10

This allows you to boot into a software that’s available over the network

Question 11

What’s a common use case for an organization that wants to install software over a network?

Answer 11

Keep OS installation files on a TFTP server so when you perform a network boot you’ll automatically be launched into the installer

Question 12

What does NTP stand for? It’s one of the oldest protocols in use today

Answer 12

Network Time Protocol

Question 13

What does NTP do?

Answer 13

NTP is used to keep clocks on a machine synchronized to a network

Question 14

What are 3 options you have to setup an NTP server for your fleet?

NTP is an important network service that should be integrated into your fleet

Answer 14

1. can use a local NTP server (your own configurations)
2. can use a public NTP server
3. can run your own local NTP server, have that point to a public NTP server

Question 15

What is Intranet?

Answer 15

an internal network inside a company (only accessible if you’re on that company’s network)

like Smalley-Wi-Fi

Question 16

What is a proxy server?

Answer 16

Receives the network traffic, relays the info to the company network (acts as a middleman for company privacy)

Question 17

What can proxy servers also be used for besides being an intermediary?

Answer 17

can be used to log and monitor internal company network activity

(no Facebook during work! websites are filtered from being accessed)

Question 18

What are 2 reasons why you would need to setup your own DNS servers if your ISP provides a DNS server anyway?

To tell the internet what…., To work on your…

Answer 18

1. To tell the internet what IP address to reach your website (if you’re running a web service)
2. To work on your server or user machines remotely (connecting to the hostname is easier than using an IP address)

Question 19

What are domain registrars?

Answer 19

Companies that provide domain names for purchase

Question 20

What are the 3 steps to setting up DNS for a website?

Answer 20

1. Purchase a domain name from a domain registrar
2. Store website files on your own web server or cloud host provider
3. Setup access to location of stored website files by providing IP address to domain registrar that’s hosting DNS for you or setup your own authoritative DNS server for your website

Question 21

Why would we want DNS for our own internal computers?

Answer 21

So we can reference a computer by name instead of IP address

Question 22

What does using a host file in networking allow us to do? [DNS]

Answer 22

Host files allow us to map IP addresses to host names manually

Question 23

In Linux, our host file is called?

Answer 23

etc/hosts

Question 24

Local host is commonly used as a way to….? Linux

Answer 24

access a local web server

[the IP address at the top of etc/hosts is the computer’s]

Question 25

A DNS query first checks ….. , then our…..?

Answer 25

A DNS query first checks our local host file, then our local DNS servers

(not feasible to have a PC’s hostname on a local host file because to access the computer by hostname you’d have to change every host file on every computer in the fleet)

Question 26

What are the 3 DNS options we can use for internal networks?

Answer 26

1. Use a local host file [dont understand why this is an option?]
2. Setup a local DNS server
3. Integrate DNS with a directory service

Question 27

If we properly set up DNS and DHCP server settings, how can they work together?

Answer 27

We can specify DNS server locations in our DHCP settings that let the 2 services sync up so when DHCP leases out new IP addresses, DNS updates its IP address mapping automatically (which IP address –> what name)

Question 28

What does the command nslookup do? Linux

Answer 28

gives us the name server of a host or domain name

Question 29

How do you ping a website in Linux?

Answer 29

ping www.google.com

Question 30

In summary, what are the 4 steps to troubleshoot a website not loading? [Linux]

Answer 30

1. check network connection by pinging an online website
2. if ok, use nslookup to verify DNS server is giving us the correct web address and copy and paste IP address it shows
3. not ok, check the IP address that shows up in ping again and paste that IP address
4. not ok, check local host file (sudo vim /etc/hosts) and delete line that points to fake IP address and save it, restart browser and done