Chapter 10: Network Naming Pg 341 - 346

CIFS

• a computer uses a CIFS broadcast to get the name of another computer
• organizes computers on a network into groups
• workgroup: a name that organizes a group of computers
• all computers within a domain authenticate to the domain controller when they log in 
• Active Directory: an organization of related computers that shares one ore more windows domains
• has no single domain controller

Chapter 10: Network Naming pg 326 - 340

Name Servers

• DNS Server: a computer running DNS sever software
• zone: a container for a single domain that gets filled with records
• record: a line in the line zone data that maps an FQDN to an IP address 
• systems running DNS server software store the DNS information
• when a system needs to know the IP address for a specifc FQDN, it queries the DNS server listed in the TCP/IP configuration
• Authoritative DNS server: a simple network usually has one DNS server for the entire network
• job is to make sure that all the other name servers are updated for changes
• a DNS server has a signle zone that lists all the host names on the domain and their corresponding IP addresses
• a single DNS domain may have a single authoritative DNS server but a number of other DNS servers 

Name Resolution

• a web browser must resolve the name to the web server's IP address to make a connection to that web server
• can be resolved in three ways
• broadcasting
• consulting the locally stored HOSTS text file
• contacting a DNS server
• to broadcast, the host sends a message to all the machines on the network 
• works for small networks 
• limited because it cannot provide name resolution across routers
• routers do not forward broadcast messages to other networks
• a HOSTS file lists the names and addresses of machines on a network 

Network + Practice Exam

Test Taken
Score Given: 6/25

Things To Remember:

1. nslooup is used for querying DNS servers to obtain domain name or IP address mapping
2. HTTPS uses SSL/TLS on TCP port 443
3. In transport mode, IPsec offers encryption.
4. TCP port 20 is used for FTP data transfer.
5. Coaxial cabling is used with BNC connectors.
6. IPv6 addresses consist of 128 bits.
7. Layer 2 tunneling Protocol offers no encryptions used with IPsecruns over UDP port 1701
8. Network Time Protocol uses UDP port 123
9. Smurf attack is an example of a Distributed Denial of Service attack.
10. CSMA/CA is the name of an access method used in wireless networks.
11. Fake logon screen on a system will most probably be a result of downloading and installing a trojan horse.
12. Internet Group Management Protocol is used for establishing multicast group memberships used on IPv4 networks.
13. IMAP4 runs on TCP 143 and is used for retrieving e-mail messages from e-mail servers.
14. MAC address's consist of 48 bits and is also known as a physical address.
15. CSMA/CD is used as an access method used in ethernet networks.
16. 802.3ae defines 10 Gigabit Ethernet

Chapter 10: Network Naming pg 317 - 322

How DNS Works 
- DNS servers use UDP port 53 and sometimes TCP port 53
- the DNS root for the entire internet consists of 13 powerful DNS server clusters all over the world
        -> has the complete definitive name resolution table
- Internet Corporation for Assigned Names and Numbers (ICANN): creates new TLDs 

Name Spaces 
- Hierarchical Name Space (used by DNS): an imaginary tree structure for possible names that can be used within a single system
       -> enables administrators to give networked systems longer names
- Flat Name Space (used by HOSTS): an undivided list containing all names
       -> all names must be absolutely unique

Chapter 9: TCP/IP Applications Pg 301 - End

Rlogin, RSH, and RCP
- Remote Login (Rlogin): you can connect and run commands by running the program with the host name of the server
       -> can configure it to log in automatically without needing to enter a username and password
       -> only connects using UNIX hosts
- Remote Shell (RSH): enables you to send single commands to the remote server
        -> runs over TCP port 514 by default
- Remote Copy Protocol (RCP): provides the capability to copy files to and from the remote server without needing FTP or NFS 

SMTP, POP3, AND IMAP4
- Simple Mail Transfer Protocol (SMTP): used to send e-mail
- Post Office Protocol 3 (POP3): receives e-mail from SMPT using TCP port 110
- Internet Message Access Protocol 4 (IMAP4): retrieves e-mail from an e-mail server
         -> enables you to search through your messages on the mail server to find specific keywords
         -> supports the concept of folders
       
File Transfer Protocol (FTP)
- original protocol used on the internet for transferring files
- can transfer while keeping security and data integrity
- uses TCP ports 21 and 20 by default

Things To Remember: 

1. Secure Sockets Layer (SSL) is a protocol developed by Netscape for transmitting private documents over the internet. SSL works by using a public key to encrypt sensitive data.
2. URLs that use an SSL connection start with HTTPS 
3. SSH encrypts data and is more secure than Telnet. SSH uses port 22.
4. Telnet is used to issue commands to a remote server

Chapter 9: TCP/IP Applications pg 286 - 300

Connection Status 
- open port: a socket that is prepared to respond to any IP Packets destined for that socket's port number
           -> every application has an open port
           -> to see all listening ports time netstat -an into a command prompt

Rules for Determining Good vs. Bad Communications

1. Memorize known ports for common TCP/IP applications 
2. Learn netstat such as -an, -n, -o, and -b
3. get rid of bad or unnecessary processes 

The World Wide Web

- composed of servers that s tore specially formatted documents using Hypertext Markup Language (HTML)

        -> many pages now are written using HTML5

- Extensible Markup Language (XML): provides the basic format or language for everything from application programming interfaces to word documents

HTTP

- Hypertext Transfer Protocol (HTTP): underlying protocol used by the web 

           -> relays commands executed by users without reference to any commands previously executed

Web Servers and Web Clients

- web server: a computer that delivers web pages

           -> listen on port 80 

- Internet Information Services (IIS): enables you to set a maximum connection limit on your web server based on available bandwidth and memory 

- uniform resource locator (URL): complete name of a web server

Secure Sockets layer and HTTPS
- Secure Sockets Layer(SSL): a protocol for transmitting private documents over the internet 

- Hypertext Transfer Protocol over SSL (HTTPS)

- Transport Layer Security (TLS)

Chapter 9: TCP/IP Applications pg 275 - 286

TCP
- Transmission control Protocol (TCP): enables connection-oriented communication in networks that use the TCP/IP protocol suite
- TCP three-way handshake
- most TCP/IP applications use TCP because connection-oriented sessions are designed to check for errors

DHCP
- Dynamic Host configuration Protocol
- can't assume another computer is ready on either side of the session
- uses port 67 for sending data the the DHCP server

NTP/SNTP
- Network Time Protocol (NTP)
- Simple Network Time Protocol (SNTP)
- synchronize the clocks of devices on the network

TFTP
- Trivial File Transfer Protocol (TFTP): enables you to transfer files from one machine to another
- has no data protection so it is not used for communication between computers across the internet

ICMP
- works at layer 3 to deliver connectionless packets
- handles disconnect messages

IGMP
- Internet Group Management Protocol (IGMP): enables routers to communicate with hosts to determine a "group" membership

Registered Ports
- ports numbers from 1024 to 49151 are called registered ports
- anyone can use these port numbers for their servers
- 0 to 1023: well-known ports
- 1024 to 4951: Registered ports
- 49152 to 65535: dynamic or private ports
- socket: connection data stored on a single computer
- socket pairs: the connection data stored on two computers
- connection: the whole interconnection