Certiport Networking Certification

SMTP (Simple Mail Transfer Protocol)

25 TCP

FTP

20, 21 TCP

HTTPS (Hypertext Transfer Protocol Secure)

An encrypted version of HTTP. It uses port 443.

IoT (Internet of Things)

a large network of physical objects including sensors and equipment

OSI Layer 1 - Physical

Protocols: 100BaseT, 1000BaseT.

Device: hubs, RJ45, repeater.

OSI Layer 2 - Data Link

Protocols: Ethernet, MAC, Frames, crc.

Device: NIC, switch, bridge, WAPs.

OSI Layer 3 - Network

Logical addressing, switching type, route discovery/selection, and packet ordering.

IP, ICMP, ARP, RIP, IPX

Device: Router

OSI Layer 4 - Transport

Protocols (TCP/UDP), windowing, buffering

Device: N/A

OSI Layer 5: Session

Protocols: Log on/ Log off, NetBIOS, Negotiation

Device: N/A.

OSI Layer 6: Presentation

Protocols: compression, encryption.

Device: N/A.

OSI Layer 7: Application

Protocols: FTP, HTTP, HTTPS, POP3, SMTP, IMAP

Device: Gateway

UDP

connectionless messaged based protocol with best effort service.

TCP

Transmission Control Protocol, connection oriented protocol with guaranteed service

ARP

Address Resolution Protocol, resolves IP addresses to MAC addresses.

Loopback address

127.0.0.0 - 127.255.255.255

Multicast address

224.0.0.0 to 239.255.255.255

Private Network addresses

192.168.0.0 - 192.168.255.255

Class A IP Address

1-126 Leading bits.

128 Networks.

16,777,214 Hosts per Network.

Default Subnet Mask 255.0.0.0

Class B IP Address

128-191 Leading bits.

16,384 Networks.

65,534 Hosts per Network.

Default Subnet Mask 255.255.0.0

Class C IP Address

192-223 Leading bits.

2,097,152 Networks.

254 Hosts per Network.

Default Subnet Mask 255.255.255.0

Class D IP Address

224-239

Used for multicast testing

Star Topology

Each computer is connected by a single cable.

Their is a central connectivity device.

Ring Topology

Each workstation acts as a repeater.

Each node is connected to 2 other nodes.

2 Advantages of Star vs Ring

Flexibility and scalability

Mesh advantages

Redundancy, every machine connected to others

802.11a

5 GHz, 54 Mbps

802.11b

11 Mbps, 2.4 GHz

802.11g

54 Mbps, 2.4 GHz

802.11n

600 Mbps - 5GHz and 2.4GHzm, MIMO

uses dual antennas, MIMO, channel bonding, frame aggregation

802.11ac

2.4GHz 5.0aGHz 5.0GHzb 1300mbps

MU-MIMO

SSL VPN

allows a remote user to connect to a private network from anywhere on the internet.

Layer 2 Tunneling Protocol (L2TP)

creates an unencrypted connection between 2 network devices.

site-to-site VPN

securely connects 2 portions of a private network or 2 private networks.

MAC/HW/physical address

48 bits

Logical address IPv4

32 bits

IPv6

128 bits per address

Internet

interconnected networks

Intranet

allows only users within an organization access

Extranet

allows certain business and educational organizations to access

Unicast

1 to 1 communications

Multicast

1 to many communications

Broadcast

1 to all communications

Virtual machine

software enabled operating system

Virtual Private Network (VPN)

Network Service to encrypt and secure a connection to company LAN (DirectAccess = without any user action)

Remote Desktop: Port 3389

allow remote connection to another computer system

CSMA/CA

Carrier Sense Multiple Access/Collision

Security is a concern wireless networks because of the radio broadcast access method (CSMA/CA)

MU-MIMO - Multi User AND Multiple Input and Multiple Output

Allows a WiFi router to Communicate w/ multiple devices simultaneously (no waiting and this is faster).

SSID (Service Set Identifier)

Access Point Broadcast ID

WEP (Wired Equivalent Privacy)

Weak and susceptible to hacks - Not encrypted

WPA

Wireless Protected Access

Stronger

WPA2

WiFi Protected Access 2

WPA2-PSK (Pre-shared key)

Strongest and recommended

WPA/WPA2-Enterprise

802.1x, needs Radius server, various EAP's can be used

Uses a RADIUS Server for companies

802.1x

Uses security certificates

Central Device of a star

Switch or Hub

VLAN(Virtual Local Area Network)

treat it like a subnet but with more security

Replace the word 'VLAN' with the word 'subnetting',

3 Properties of VLANs

1)Requires a router

2) Isolate traffic

3) Create same LAN regardless of physical location, reduce nodes in broadcast

Cat 3 (Category 3)

10Mbps 100m (10BaseT)

CAT 5(Category 5)

100Mbps 100m (100BaseT)

Cat 5e (Enhanced Category 5)

1000Mbps 100m (1000BaseT)

CAT 6(Category 6)

1Gbps/10Gbps 100m/55m (1000BaseT)

What is minimum cable needed for 100Mbps?

Cat 5

What is the max distance of UTP 5 cable?

99.97m 328 feet

Which can travel the furthest distance multi-mode or single-mode fiber?

Fiber Optic Cables support splicing and requires polished connectors

CSMA/CD (Carrier Sense Multiple Access with Collision Detection)

detects collisions and listens for when the media is idle to send

Hubs

Simple devices that connect network components, sending a packet of data to all other connected devices

always floods all ports and is less efficient

Switch

A computer networking device that connects network segments

Associates network Address to Port, uses switching table

sends packets to destination ports if it knows where to go

floods all ports if it does not

can send and receive simultaneously

sends broadcast to all ports

Multi-layer or Layer 3

provide Layer 3 functions and can understand IP addresses where Layer 2 switches cannot

Managed Switches

can create VLANs and use trunk ports to send VLAN traffic

Only Managed switches supports VLANs and remote configuration unmanaged one cannot

Routers

devices that connect different networks together

are TCP/IP enabled and most popular type network today

forward traffic to other networks

Firewall

software that runs on servers (often routers) that only allows traffic through according to some set of security rules.

Device that protects internal network from internet

2.4Ghz

is affected by cordless phones, microwaves, fluorescent lights

Class A IP Address

Address: 1-126

Private Range: 10.x.x.x

Default mask: 255.0.0.0

Example: 63.0.0.0

Class B IP Address

Address: 128-191

Private Range: 172.16.x.x

Default mask: 255.255.0.0

Example: 133.0.0.0

Class C IP Address

Address: 192-223

Private Range: 192.168.x.x

Default mask: 255.255.255.0

Example: 200.0.0.0

Class D IP Address

Address: 224

Private Range:

Default mask: Multi-task

Example: 224.0.0.0

loopback address

Address: 127.0.0.1 - 127.255.255.255

Private Range:

Default mask:

Example:

NAT/PAT (Network Address Translation/Port Address Translation)

masks internal IP addresses private/public

IPv6 Addresses

are 128-bit hexadecimal numbers

(example: 2001:7120:0000:8001:0000:0000:0000:1F10).

only 1 set of :: and made up of 8 16bit blocks

::1 is the loopback address. Unicast IPv6 addresses are assigned to a single interface and are the most common type.

FE80

APIPA address

FEC0

Site Local address

Teredo

Ipv4 to Ipv6 tunneling (Converting protocols that allows IPv4 and IPv6 to work together.)

Router Static Route (default route/gateway)

Set by Administrator

Router Dynamic Routes

set by routing protocols (RIP, OSPF, EIGRP)

DHCP (Dynamic Host Configuration Protocol)

UDP 67, 68

A network service that provides automatic

assignment of IP addresses and other TCP /IP configuration information.

ipconfig /all

Show all TCP/IP details

displays client IP information

Assigns addresses automatically for a lease amount of time created by the scope

Reservations and exclusions are for static IP addresses

APIPA (Automatic Private IP Addressing)

Feature of Windows that automatically assigns an IP address to the system when the client cannot obtain an IP address automatically.

169.254.x.x address assigned when DHCP Server is down or not available

When DHCP is down..

Computer will try to re-lease at 50%

DHCP relay agent

is needed if the client is on a different subnet

DNS (Domain Name System)

53 TCP/UDP

Domain Name Service: Resolves FQDN to IP addresses

DNS Record types

Hosts file stores all the DNS records

A = host record

AAAA = IPv6 host record

MX = Email record

CNAME = Alias record

PTR is the reverse IP address to the Domain Name

A - Record - Domain name to IP address

mail.abc.com mail

host computer/Server, abc = domain name

FTP (File Transfer Protocol)

Data 20

FTP (File Transfer Protocol)

Control 21

SSH (Secure Shell)

TCP 22

UDP 22

Telnet (Telecommunication Network)

TCP 23

SMTP (Simple Mail Transfer Protocol)

TCP 25

DNS (Domain Name System)

53

DHCP (Dynamic Host Configuration Protocol)

UDP 67, 68

HTTP (Hypertext Transfer Protocol)

TCP 80

POP3 (Post Office Protocol version 3)

TCP 110