Network Services

What is beneficial about an Intranet?

They can provide a wide range of info, and are meant to improve productivity by giving employees a greater medium to share information.

When you change your localhost to something like www.google.com, why does it take you back to your local computer?

This is because a DNS query first checks our local host file, then our local DNS servers. So, if there's an entry for google.com in our host file, you go to that IP address instead.

Why do airports utilize synchronized clocks systems, and many of their systems use NTP?

This is because the info that you see on your departure and arrival screen has to match the time that the air traffic control team sees for their airplanes.

How do you set up a local NTP server?

You can install NTP server software on your management server. Then you install NTP clients on your machines and tell those computers which NTP service to sync their time to.

Why is setting up a local NTP server a great option?

You can then manage the entire process from end to end.

What is commonly used as a way to access a local web server?

localhost

How does DNS get set up for a website?

1. First, we need a domain name which we can purchase from domain registrars. 2. Once we have our domain name, we have to point our website files to this domain name using a cloud hosting provider or stored on your own servers.

What are 2 reasons why you need to set up your own DNS service when maintaining a company's IT infrastructure?

1. If you're running a web service, like a website, you want to be able to tell the Internet what IP address to reach your website at. To do that, you need to set up DNS. 2. You probably want to work on your server or user machines remotely. In theory, you could remote access into them through an IP address but you could also just use an easy to remember host name. To do that, you need DNS to map the IP address to the host name.

What are two ways to point a domain name to where web content is located?

1. Most domain registrars can provide you with DNS settings and you can give the IP address of where your content is stored. 2. If you decide not to use your domain registrar to host DNS for you, then you have to set up an authoritative DNS server for your website.

What are 3 ways that an IT support specialist or sysadmin can set up an NTP server for an organization?

1. They can use a local NTP server. 2. They can use a public NTP server. 3. They can run their own NTP server and have that point to a public NTP server.

What are a few ways to map our internal computers to IP addresses?

1. Using a local host file which contains static IP addresses to hostname mappings. 2. We can set up a local DNS server that contains all the organization's computer names mapped to their IP addresses. 3. An internal network can be integrated with a directory service which handles user and machine info in its central location like, active directory and LDAP. Once we set up DNS in our directory service, it will automatically populate with machine to IP address mappings.

What is a network service that's commonly used in organization?

A file transfer service

Network Time Protocol (NTP)

A protocol that is used to synchronize the time on a computer from across a network.

FTP (File Transfer Protocol)

A protocol used to move files and folders over a network or the Internet.

localhost

A reserved name that corresponds to the loopback address, 127.0.0.1. This is commonly used as a way to access a local web server.

SFTP (Secure File Transfer Protocol)

A secure version of the file transfer protocol. During this protocol's process, data is sent through SSH and is encrypted.

TFTP (Trivial File Transfer Protocol)

A simple version of the file transfer protocol that uses UDP as the transport protocol, and does not require a logon to the remote host.

What can we use to store and serve content to clients that request our services?

A web server

Proxy server

Acts as an intermediary between a company's network and the Internet. They receive network traffic and relay that info to the company network.

Intranet

An internal network inside a company; accessible if you're on a company's network.

What are two popular DNS software options?

BIND and PowerDNS

Why should you only store generic files that do not need to be secure in TFTP?

Because TFTP doesn't require user authentication like FTP.

How does FTP work?

Clients that want to access an FTP server, have to install an FTP client. On the FTP server, we install the software that allows us to share info located in the directory on that server.

If you don't want to use static IP addresses, but want to dynamically assign IP addresses to computers instead, what network protocol can you use?

DHCP

If you want to point a domain name to a web server or use hostnames within your company, what network protocol can you use?

DNS

What is an important network service to set up and maintain when managing a company's IT infrastructure?

DNS

What can you specify in a DHCP configuration settings?

DNS server locations

What is an authoritative DNS server?

DNS servers that know exactly what the IP address is for the domain name.

Why do you have to investigate which specific DHCP server software manufacturer you want to use?

Different DHCP server software manufacturers have different configuration setting layouts.

You're the sole IT employee at your company, and you don't know how many users or computers are in your organization. What can you use to easily manage the users in your company?

Directory services, like ActiveDirectory and OpenLDAP, help manage users and computers in a company.

Which file transfer protocol isn't a very secure way to transfer data because it doesn't handle data encryption?

FTP

What are 3 file transfer protocols?

FTP, SFTP, and TFTP

True or False: Intranets are seen everywhere and have no real value.

False; Intranets are most commonly seen in large enterprises, and can be an incredibly valuable tool for employee productivity.

What are proxy servers useful for?

For fighting privacy and security on the Internet, and regulating access inside a company.

What are 2 examples of domain registrars?

GoDaddy.com and BlueHost.com

When would you want to look at network file storage services over FTP clients?

If you just want to share files between your computers in a secure way and have a nice directory where you can access all the shared files instead of transferring them to your machine.

Domain Name System (DNS)

Maps human-understandable names to IP addresses.

What features does a proxy offer?

Network privacy, network traffic monitoring, and internet traffic filtering.

What service can you use to keep time synchronized across the machines on your fleet?

Network time protocol; NTP

What happens if you don't set up DNS correctly?

No one will be able to access websites by their names.

Where can website files be stored?

On a cloud hosting provider or on your own servers.

What are 2 network services that are used internally in an IT enterprise environment, to improve employee productivity?

Privacy and security

How do you set up NTP using a public NTP server?

Public NTP servers are managed by the other organizations that your client machines connect to in order to get synchronized time.

PXE (preboot execution environment)

Refers to a client that can boot from a NIC. Clients enabled with this include a NIC and BIOS that can be configured to boot from the NIC instead of a hard drive. It is often used to allow clients to download images.

What is one benefit of using TFTP over SFTP?

Simpler transfer without authentication

Why would a company use a proxy server?

So company network traffic is kept private from the Internet.

Besides setting up DNS for a website, what is another reason we might want our own DNS servers?

So we can map our internal computers to IP addresses.

A common use case for organizations that want to install software over a network is to keep OS installation files in a TFTP server. Why is this?

That way, when you perform a network boot, you can be automatically launched into the installer.

How does a proxy server keep a company's network traffic private from the Internet?

The Internet gets traffic through a proxy server, but it doesn't know where it originally came from. It only knows the proxy.

What is one of the oldest Internet protocols in use today?

The network time protocol or NTP

Why would you specify DNS server locations in a DHCP configuration settings?

The two servers can sync up and when DHCP leases out new addresses, DNS updates IP address mappings automatically.

What's one way proxy servers can be used to monitor and log internal company network activity?

They can be configured so that certain websites are filtered from being accessed.

Why would you want to use PXE to boot?

This allows you to boot into software that's available over the network.

Why is using a public NTP server a good option?

This is a good way to utilize NTP without having to run a dedicated NTP server.

If you use a website host provider, you might see that they have an FTP connection already available for use. Why?

This is so they can easily copy files to and from your website.

Why is it a good practice to run your own NTP server and have it point to a public NTP server?

This makes it so that you don't connect all your clients to a public NTP server, and you don't have to measure time synchronization.

Why would we use a DNS server to map our internal computers to IP addresses?

This way, we can reference a computer by name, instead of IP address.

There are some security services, like Kerberos and network authentication protocol, that depend on what being consistent across the network to work?

Time

What is a popular use of TFTP?

To host installation files

What do host files in networking allow us to do?

To map IP addresses to host things manually.

If you have a large fleet of thousands of machines, what is the best way to set up NTP?

To run your own NTP servers.

What is FTP primarily used for today?

To share web content.

True or False: NTP is an important network service that you should definitely integrate into your own fleet.

True

True or False: Typically, domain registrars also provide cloud hosting services but they can charge you a monthly fee to host your web files for you.

True

What do we need to do if clients want to reach our website?

We need to set up DNS so that they can just type a URL to find us.

How does DNS work?

When you connect to a network, you're using the DNS server address that was provided by the router you connected to. It updates your network setting to use that network server address, which is usually your ISP's DNS server. From there, you're able to access pretty much any website.

What happens if you change your localhost to something like www.google.com?

When you open a web browser to www.google.com, it doesn't take you anywhere. It just takes you back to your local computer.

When managing IT infrastructure, what are your two options when you want to connect a computer on a network?

You can grant it a static IP address or give it a DHCP assigned IP address.

How do you make a scalable option instead of entering the IP address and host name in your host file for every single computer in your fleet?

You can set up a local DNS server that contains all the organization's computer names mapped to their IP addresses. Then, you change your network settings for all of the computers to use as DNS server instead of the one given to you by the ISP.

When managing IT infrastructure, what do you have to do when you use a static IP address?

You have to keep track of every IP address you assign a computer and manually entered in the network settings.

What might you want to do since you can't depend on the hardware itself to keep consistent time?

You might want to set up an NTP server.

What do you need to configure a DHCP server?

You need to figure out which IP range you can use to assign IP addresses. If you want to integrate with DNS, you need the address of your local DNS servers; what gateway you should assign, and the subnet mask that gets used. Once you solve the DHCP server software, you need to configure the settings with this info.

What does it mean once you turn on your DHCP server and your client is set to receive DHCP addresses instead of static IP addresses?

You should have working DHCP settings.

What happens if you enable DHCP over static IP addresses?

Your computers will be leased an IP address from a DHCP server. They'll automatically get IP addresses, and you don't have to worry about manually setting up addresses. If you ever decide you need to expand your IP address range, you don't have to change anything on the client machines either, it just happens automatically.