Lesson 7 - Chapter 2: Internet Application Protocols Flashcards
What does protocol mean?
a set of rules
Each ____ protocol has its own rules and its own port numbers
Internet
For the most part, all apps of the same type use the same ____
protocol
(browsers = HTTP/HTTPS, email = POP3 or IMAP4 to receive and SMTP to send it)
What does POP3 stand for? What is it used for?
Post Office Protocol 3 (POP3)
to receive mail
What does IMAP 4 stand for? What is it used for?
Internet Message Access Protocol 4 (IMAP4)
The HTTP protocol is used for what function? What is its port number?
Web pages; Port 80
The HTTPS protocol’s function is? What is it’s port number?
Secure web pages; Port 443
FTP protocol is used for what function? What is its port number?
File transfer; Port 20, 21
SFTP protocol is used for what function? What is its port number?
Secure file transfer; Port 22
IMAP protocol is used for what function? What is its port number?
Incoming email; Port 143
POP3 protocol is used for what function? What is its port number?
Incoming email; Port 110
SMTP protocol is used for what function? What is its port number?
Outgoing email; Port 25
Telnet protocol is used for what function? What is its port number?
Terminal emulation; Port 23
SSH protocol is used for what function? What is its port number?
Encrypted terminal emulation; Port 22
RDP protocol is used for what function? What is its port number?
Remote Desktop; Port 3389
What are the 10 application protocols?
- HTTP
- HTTPS
- FTP
- SFTP
- IMAP
- POP3
- SMTP
- Telnet
- SSH
- RDP
What are utility protocols?
the protocols that handle important jobs behind the scenes to ensure application protocols we see run well
(DNS, DHCP, etc)
DNS protocol is used for what function? Is it TCP or UDP? What is its port number?
Allows the use of DNS naming; UDP; Port 53
DHCP protocol is used for what function? Is it TCP or UDP? What is its port number?
Automatic IP addressing; UDP; Port 67, 68
LDAP protocol is used for what function? Is it TCP or UDP? What is its port number?
Querying directories; TCP; Port 389
SNMP protocol is used for what function? Is it TCP or UDP? What is its port number?
Remote management of network devices; UDP; Port 161
NetBIOS/NetBT protocol is used for what function? Is it TCP or UDP? What is its port number?
Legacy communication services on LANs;
TCP/UDP
TCP = Port 137, 139
UDP = Port 137, 138
SMB/CIFS protocol is used for what function? Is it TCP or UDP? What is its port number?
Windows naming/folder sharing;
TCP/UDP
TCP = Port 139, 445
UDP = 137, 138
If you have a choice between POP3 or IMAP4 for email, which should you always choose? Why?
IMAP4 because POP3 offers ZERO security
What does HTTP and HTTPS stand for?
HTTP = HyperText Transfer Protocol
HTTPS = HyperText Transfer Protocol Secure
A web browser uses what 2 protocols to request a web page from a site’s web servers?
- HTTP
- HTTPS
What is a web server?
servers running specialized software designed for serving websites
HTTP isn’t secure so what does that mean an attacker can do?
read any packets they intercept
What websites use HTTPS?
Nearly every website
(In the past, only sites that required users to sign in used HTTPS)
What are 3 examples of an attacker that is attempting to compromise your systems, network, or data?
- Lone hacker trying to breach system
- State surveillance agency monitoring traffic at your ISP
- malware-compromised router that can modify/redirect your packets
Ways to access email boil down to what 2 ways?
- Generic email client applications you can configure to check many accounts
- Clients tailored around a single email service (pre-configured)
How do you have to configure generic mail clients?
you must manually configure them with the address of your incoming and outgoing mail servers
What does SMTP stand for? What is it?
Simple Mail Access Protocol, the protocol used by outgoing mail servers
How do you get the addresses of the incoming/outgoing mail servers to manually configure the generic mail clients?
from your email provider (ISP, company, school, org)
Why are the days of configuring mail apps with POP3 and IMAP4 numbered?
Many ISPs, businesses, and domain hosting services are switching to Microsoft-Exchange based services
What does Microsoft-Exchange services offer?
the servers provide email, calendars, and instant messaging for larger organizations
Can generic email clients access Microsoft Exchange accounts?
yes, they use your email address to locate the Exchange server and if compatible will self-configure after signing in
What should you do when you are given the name of a POP3 or SMTP server?
Use ping to get the IP for the device and write it down in case you ever stop getting your mail and you can type in the IP address to see if the DNS server is working
(if you can connect via IP address, DNS is not working)
What does end-to-end encryption mean?
you encrypt the message before it leaves your device, and the recipient decrypts it on the other end
What do many modern email servers use to provide transit encryption? (2)
SSL or TLS
What does SSL and TLS stand for?
SSL = Secure Sockets Layer
TLS = Transport Layer Security
What is transit encryption?
secures your message while it is in transit between your system and the mail server
Which is stronger, SSL or TLS?
TLS
What does FTP stand for?
File Transfer Protocol
Where would you use FTP?
Some web browsers have partial support built in, but there are also dedicated FTP client programs such as FileZilla or Cyberduck
What does file transfer protocol do?
used for uploading and downloading files from a remote FTP server
With public and private FTP sites, which one supports anonymous logins and which have fields to enter username and password?
Public sites support anonymous logins
Private sites you can enter username and password
How do you log into an FTP site with a browser?
you add your user name to the URL
(ftp://melaniec@ftp.example.com)
Is FTP secure?
No, like other basic protocols FTP is unsecure
(but there are secure versions like SFTP and FTPS)
What is Telnet?
a terminal emulation program (like CLI) that enables authenticated users to run commands on a remote system (like a server or router)
Is Telnet secure? In what kind of network should you use it in?
No, it sends user names and passwords as clear text so you should only use it within your LAN
What does SSH stand for?
Secure Shell
What is Secure Shell (SSH)?
Another terminal emulation program that encrypts the entire connection and supports tunneling files (like when using FTP) and TCP/IP traffic through its secure connection
(largely replaced Telnet for this reason)
___ and ___ lets you issue commands from a remote CLI
SSH and Telnet
Remote Desktop software mostly makes use of which 2 protocols?
- Remote Desktop Protocol (RDP)
- Virtual Network Computing (VNC)
What is TightVNC?
a cross platform remote desktop software that enables you to run and control a Windows system remotely from your Mac and vice versa
What is the name of Microsoft’s remote desktop software?
Remote Desktop Connection
What does Remote Desktop Connection do?
enables you to connect to and control a remote server with a full GUI
(your desktop becomes the server desktop)
What is the name of the Remote Desktop Connection executable file?
mstsc.exe
How do you open Remote Desktop Connection from a CLI or the search bar?
type “msts”
Which Windows edition can serve as a Remote Desktop client?
Any Windows edition can serve as a RD client
(it can connect to another computer remotely)
What editions can be used as a Remote Desktop server?
Pro, Enterprise, and Education editions
(accessed remotely by another computer)
What is Windows Remote Assistance?
enables techs to see what the client sees and use the system (with permission) to troubleshoot
How does Windows Remote Assistance work?
- You receive the support request via email
- Log on the user’s system
- Take the driver’s seat (with permission)
In what editions is Windows Remote Assistance available on?
any Windows version/edition
How do you open Windows Remote Assistance?
Start > Remote Assistance > Invite someone to connect to your PC (or offer to help)
What is the macOS’s version of Windows Remote Assistance?
Enable screen sharing in System Preferences for remote access and light troubleshooting and collaboration
(Apple sells RD products to business customers)
In all remote desktop methods, the connecting system is a ____ and the remote system is a ____
client, server (providing access to its own desktop)
How do you configure whether your system can act as a Remote Desktop server?
System > About > Remote Desktop
(Windows Home edition does not)
What does VPN stand for?
Virtual Private Network
What is a VPN?
uses encrypted tunnels between a computer (or remote network) and the Internet to create a private network
When it comes to VPNs, what are endpoints?
the ends of the tunnel where data is encrypted/decrypted
How do SSH tunnels work?
the client for the application sits on one end and the server on the other
What can act as an endpoint for a VPN (2)?
- software running on a computer
- dedicated Internet appliance such as an endpoint management server
How does a VPN work (in detail)?
VPN software/server sets up endpoints (with their own LAN IP address) at each end of the encrypted tunnel to join computer/networks together as if on the same LAN and direct traffic.
What does PPTP stand for?
Point to Point Tunneling Protocol
What does RRAS stand for?
Routing and Remote Access Service
(available on Server versions of Windows)
How do PPTP and RRAS work together?
PPTP places endpoints on the client and uses the RRAS special remote access server program to enable individual clients (employees on the road) to access the office network
How does a VPN act as a NIC?
It’s endpoints act like virtual NICs that (like any NIC), get an IP address from the DHCP server (from the home/office network)
How is traffic directed when using a VPN?
Internet traffic goes through your, for example, office FIRST
(your client’s traffic will use the office LAN and its internet connection making web browsing on VPN very slow)
What does the LDAP protocol do and what does it stand for?
Lightweight Directory Access Protocol
enables operating systems and applications to access directories
(Windows Server uses this to work with Active Directory and add each computer’s information)
What is Simple Network Management Protocol? (SNMP)
enables remote query and remote configuration of anything on a network
(popular protocol to check on your network, Network+ techs use it)
What does SMB stand for and what does it do?
Server Message Block
Window’s network file/print sharing protocol (the choice for LAN file servers)
What is the Linux version of SMB?
SAMBA
(network file/print sharing protocol)
On a local LAN, what assigns IP address automatically?
The switch or router for internal addresses
(the ISP’s assigned IP address is to access the Internet)
What is NetBIOS?
an older, outdated protocol that enabled devices to communicate on LANs (before Internet and IP addresses)
