2. Networking (20%) Flashcards
Port 20/21
File Transfer Protocol (FTP)
Port 22
Secure Shell (SSH)
File Transfer Protocol (FTP)
is optimized to do what it says it does—transfer files
- includes both uploading and downloading files from one host to another
Secure Shell (SSH)
is a connection-oriented protocol that can be used to set up a secure Telnet session for remote logins or for remotely executing programs and transferring files
- originally designed to be a replacement for the unsecure telnet command
- a connection-oriented protocol, it has higher overhead than UDP and is a little slower.
Port 23
Telnet
Telnet
Someone using this can log into another machine and “see” the remote computer in a window on their screen
Port 25
Simple Mail Transfer Protocol (SMTP)
SMTP (Simple Mail Transfer Protocol)
is the protocol most commonly used to send email messages
- the protocol used to send email from mail server to mail server as well as from a mail server to an email client
Port 53
Domain Name System (DNS)
DNS (Domain Name System)
is to resolve hostnames to IP addresses
- let’s say that you open your web browser and type in a Uniform Resource Locator (URL) such as https://www.wiley.com
Port 67/68
Dynamic Host Configuration Protocol (DHCP)
DHCP (Dynamic Host Configuration Protocol)
dynamically assigns IP addresses and other IP configuration information to network clients
- is connectionless, which makes it a bit faster, but it doesn’t guarantee packet delivery
Port 80
Hypertext Transfer Protocol (HTTP)
HTTP (Hypertext Transfer Protocol)
It manages the communication between a web server and client, and it lets you connect to and view all the content that you enjoy on the Internet
- All the information transmitted is plain text, which means that it’s not secure
Port 110
Post Office Protocol 3 (POP3)
POP3 (Post Office Protocol 3)
the preferred protocol for downloading email for a long time
- replaced in most installations by IMAP4
Port 137/139
Network Basic Input/Output System (NetBIOS)/NetBIOS over TCP/IP (NetBT)
Network Basic Input/Output System (NetBIOS)
is an application programming interface (API) that allows computers to communicate with each other over the network
- It works at
Layer 5 of the OSI model
Port 143
Internet Message Access Protocol (IMAP)
Internet Message Access Protocol (IMAP)
is a secure protocol designed to download email. Its current version is version 4, or IMAP4
- works in connected and disconnected modes
- lets you store the email on the server, as opposed to POP3, which requires you to download it
- allows multiple clients to be simultaneously connected to the same inbox
Port 161/162
Simple Network Management Protocol (SNMP)
Simple Network Management Protocol (SNMP)
gathers and manages network performance information
- mostly used to monitor connectivity devices, many other network devices are SNMP-compatible as well
Port 389
Lightweight Directory Access Protocol (LDAP)
Lightweight Directory Access Protocol (LDAP)
is a directory services protocol based on the X.500 standard
- designed to access information stored in an information directory
Port 443
Hypertext Transfer Protocol Secure (HTTPS)
Hypertext Transfer Protocol Secure (HTTPS)
To encrypt traffic between a web server and client securely
- are secured using either Secure Sockets Layer (SSL) or Transport Layer Security (TLS)
- a connection-oriented protocol, it has higher overhead than UDP and is a little slower.
Port 445
Server Message Block (SMB)/Common Internet File System (CIFS)
Server Message Block (SMB)/Common Internet File System (CIFS)
is a protocol originally developed by IBM but then enhanced by Microsoft, IBM, Intel, and others.
- used to provide shared access to files, printers, and other network resources and is primarily implemented by Microsoft systems
Common Internet File System (CIFS)
is a Microsoft-developed enhancement of the SMB protocol, which was also developed by Microsoft
- used to share files and printers between computers, regardless of the operating system that they run
- default file and print sharing protocol in Windows
Port 3389
Remote Desktop Protocol (RDP)
Remote Desktop Protocol (RDP)
allows users to connect to remote computers and run programs on them
- is available for Windows, Linux, macOS, iOS, and Android
Trivial File Transfer Protocol (TFTP)
Transmitting configurations to
and from network devices. It can transfer files much like FTP, but it’s much simpler and faster
- is connectionless, which makes it a bit faster, but it
doesn’t guarantee packet delivery
Router
highly intelligent devices that connect multiple network types and determine the best path for sending data
- They connect multiple networks to each other, which none of the other devices we have discussed do
- operate at the Network layer (Layer 3) of the OSI mode
Switches
work at Layer 2 and they provide centralized connectivity, just like hubs
- examine the Layer 2 header of the incoming packet and forward it properly to the right port and only that port
Unmanaged Switch
it connects two or more computers, and passes along all traffic sent to a MAC address to its port
Managed switch
adds the ability to configure ports, manage traffic, and monitor traffic for issues
- cost more but provide features such as quality of service (QoS), redundancy, port mirroring, and virtual LANs (VLANs)
Access Points
any point that allows a user on to a network
- On a wired network, this means a hub or a switch, both of which we will cover shortly
Patch Panel
is essentially a large hub that is rack mounted. It houses multiple cable connections but possesses no network intelligence
- Its sole purpose is to connect cables together
Firewall
a hardware or software solution that serves as your network’s security guard
- they protect your network resources from hackers lurking in the dark corners of the Internet
- they can simultaneously prevent computers on your network from accessing undesirable content on the Internet
Power over Ethernet (PoE)
provides for electricity
over Ethernet cables
- useful in situations where you need a wireless access point in a relatively remote location that does not have any power outlets
Power over Ethernet injectors
a device that sits
between the switch and the access point (called a midspan device) whose sole purpose is to supply power via the Ethernet connection
Hub
a device used to link several computers together
- They simply repeat any signal that comes in on one port and copy it to the other ports (a process that is also called broadcasting)
- They work at Layer 1 of the OSI model
Cable Modem
most homes and many businesses now access the Internet through this
- use
television cable lines
Digital Subscriber Line (DSL)
uses existing phone lines and provides fairly reliable high-speed access
- you need a DSL modem and a network card in your computer
Optical Network Terminal (ONT)
If there is fiber in your work or home neighborhood, you need a different type of modem to connect to the ISP for Internet access
- It is closer to a modem in a sense though because it takes optical signals and changes them into electrical ones for your internal home or business network
Network Interface Card (NIC)
an expansion card that connects a computer to a network so that it can communicate with other computers on that network
Software-Defined Networking (SDN)
essentially setting up a network virtually, without the physical hardware connectivity devices that most people are used to
- it’s a network without the network hardware