Network Services
What benefits does the Domain Name System (DNS) provide?
-no need to memorize hard to remember IP addresses. -maps to a system's IP address, even if that address changes.
How many root servers are there?
13
A DNS record that's used to redirect traffic from one domain name to another is known as a _______ record.
A CNAME redirects a DNS resolution attempt from one domain name to another.
The final step of the DHCP Discovery process is known as ______.
A DHCPACK is the final step in the DHCP Discovery process.
DHCP (Dynamic Host Configuration Protocol)
A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information.
IP address ( 32 bit binary number )
A number that uniquely identifies each computer or device connected to the Internet
An IT systems engineer creates a new Domain Name System (DNS) zone that contains pointer (PTR) resource records. Which zone type has been created?
A reverse lookup zone is used to map domain names to IP addresses.
A service that might appear to be a single server to external clients, but actually represents many servers living behind it, is known as a _______.
A reverse proxy allows for a single server to appear to be the endpoint for many servers behind it.
A video conferencing application isn't working due to a Domain Name System (DNS) port error. Which record requires modification to fix the issue?
A service record is used to set parameters, like the protocol and ports used for a service with a domain name.
RIR (Regional Internet Registry)
AFRINIC - Africa, ARIN - North America APNIC - Asia Pacific LACNIC - Southern & Central America and RIPE NCC - Europe, the Middle East and Central Asia.
An A Record contains what?
An A record contains an IPv4 address.
A fully qualified domain name can contain how many characters?
An FQDN is limited to a total length of 255 characters.
DHCP Discovery
the process by which a client configured to use DHCP attempts to get network configuration information
At the very lowest level, what data does a computer understand?
Binary numbers are zeros and ones. Fortunately, computers present data in a much friendlier way.
5 types of DNS Servers
Catching name Recursive name Root name TLD name Authoritative name
Domaine Name
the term we use for something that can be resolved by DNS
The process by which a client configured to use DHCP attempts to get network configuration information is known as _________________.
DHCP Discovery is how a client determines configuration information.
Reverse lookup zone files
these let DNS resolvers ask for an IP and get the FQND associated with it returned
Along with an IP address, a subnet mask, and a name server, the other thing required for a computer to operate on a network is a _______.
Every networked device needs a gateway to know where to send network intended for outside of the local network segment.
When using Fixed Allocation DHCP, what's used to determine a computer's IP?
Fixed Allocation DHCP ensures that computers receive an IP address reserved for it via its MAC address.
What are the four things that all computers need configured in order to operate on a modern network? Check all that apply.
IP Address Default Gateway Subnet Mask Name Server
TCP/IP Model
IP Address Subnet mask Gateway Name Server
What term defines keeping the address of one computer secret from another?
Masquerading is when NAT is used to hide the IP of a computer from another.
NAT addresses concerns over the dwindling IPv4 address space by ___________________.
NAT allows networks to use non-routable address space for their internal devices.
What technique allows for inbound traffic through a NAT?
Port forwarding is a technique that allows for inbound traffic through a router configured to NAT
A new Domain Name System (DNS) server is being configured. Which record type is used to declare a new zone?
Start of Authority (SOA) record establishes a zone and maintains authority over the zone.
Top-level domain (TLD)
the last part of a domain name .com
A DNS TTL determines what?
TTL stands for Time to Live and determines how long a DNS entry can be cached.
TLD (top-level domain)
The highest-level category used to distinguish domain names-for example, .org, .com, and .net. A TLD is also known as the domain suffix.
FQDN (Fully Qualified Domain Name)
The host name combined with the host's domain name. www.google.com
When a client computer sends a request to a Domain Name System (DNS) server, what type of packet is sent?
The requesting client initiates a query with a DNS server by sending a Synchronize (SYN) packet as a first step in the three-way handshake.
The total number of IPv4 addresses is approximately:
There are approximately 4.2 billion IPv4 addresses
Two-factor authentication is_________________________.
Two-factor authentication requires a username/password and something extra.
MAC address ( 48 bit binary numbers )
Unique address embedded in network-connected devices
TXT record ( text )
Used to associate any arbitrary text with a hostname. Used as a method to detect email spoofing
Question 2 VPNs are known as a _____ protocol.
VPNs are tunneling protocols.
What transport layer protocol does DNS normally use?
While DNS over TCP does exist, UDP is the most common protocol.
A proxy is something that _______________________.
While proxies are many things, they primarily communicate on behalf of something else.
DNS (Domain Name System)
a global and highly distributed network service that resolves strings of letters into IP Addresses for you
Automatic Allocation
a range of IP addresses is set aside for assignment purposes
Dynamic Allocation
a range of IP addresses is set aside for client devices and one of these IPs is issues to these devices when they request one
Proxy services
a server that acts on behalf of a client in order to access another service Anonymity Security Content Filtering Increased performance
Reverse Proxy Server
a service that might appear to be a single server to external clients, but actually represents many servers living behind it
Anycast
a technique that's used to route traffic to different destinations depending on factors like locations, congestion or link health
two-factor authentication (2FA)
a technique where more than just a username and password are required to authenticate
Port Forwarding
a technique where specific destination ports can be configured to always be delivered to specific nodes
Port preservation
a technique where the source port chosen by a client is the same port used by the router
NAT (Network Address Translation)
a technology that allows a gateway usually a router or firewall, to rewrite the source IP of an outgoing IP datagram while retaining the original IP in order to rewrite it into the response
VPN (Virtual Private Network)
a technology that allows for the extension of a private or local network to host that might not be on that local network
TTL (Time to Live)
a value, in seconds that can be configured by the owner of a domaine name for how long a name server is allowed to cache an entry before it should discard it and perform a full resolution again
Fixed Allocation
ensures that computers receive an IP address reserved for it via its MAC address.
IANA (Internet Assigned Numbers Authority)
has been in charge of distributing IP addresses since 1988. Since that time, the internet has expanded at an incredible rate! The 4.2 billion possible IPv4 addresses have almost run out, as it's long been predicted.
A Record
is used to point a certain domain name at a certain IPv4 IP address
AAAA (quad-A)
is used to point a certain domain name at a certain IPv6 IP address
Recursive name servers
perform full DNS resolution requests
One -to-many NAT
protected IP address
PTR (Pointer) record
resolves an IP to a name
Zone files
simple configuration files that declare all resources records for a particular zone
DNS Red Robin
used to balance traffic across multiple IPs
MX Record (mail exchanger)
used to deliver email to the correct server
Domains
used to demarcate where control moves from a TLD name server to an authoritative name server
NTP (Network Time Protocol)
used to keep all computers on a network synchronized in time
CNAME record
used to redirect traffic from one domain name to another
Sub-domaine
www