1. CIS 1140 Network Fundamentals
Chapter Four: Introduction to TCP/IP Protocols
Collected and Compiled
By JD Willard
MCSE, MCSA, Network+,
Microsoft IT Academy Administrator
Computer Information Systems Instructor
Albany Technical College

2. Attention: Accessing Demos
This course presents many demos.
The Demos require that you be logged in to the Virtual Technical College web site when you click on them to run.
To access and log in to the Virtual Technical College web site:
To access the site type in the url window
Log in using the username: CIS 1140 or ATCStudent1
Enter the password: student (case sensitive)
If you should click on the demo link and you get an Access Denied it is because you have not logged in to vtc.com or you need to log out and log back in.
If you should click on the demo link and you are taken to the VTC.com web site page you should do a search in the search box for the CompTIA Network+ (2009 Objectives) Course and run the video from within that page.

3. Objectives
Identify and explain the functions of the core TCP/IP protocols
Explain the TCP/IP model and how it corresponds to the OSI model
Discuss addressing schemes for TCP/IP in IPv4 and IPv6 protocols
Discuss addressing schemes for TCP/IP in IPv4 and IPv6 and explain how addresses are assigned automatically using DHCP (Dynamic Host Configuration Protocol)
Describe the purpose and implementation of DNS (Domain Name System)
Identify the well-known ports for key TCP/IP services
Describe how common Application layer TCP/IP protocols are used

4. Network Protocols
A Protocol is a set of standards or rules that governs how networks communicate
Protocols often provide services, such as or file transfer. Most protocols are not intended to be used alone, but instead rely on and interact with other dependent or complimentary protocols
Protocols vary according to their purpose, speed, transmission efficiency, utilization of resources, ease of setup, compatibility, and ability to travel between different LANs.
Multiprotocol networks: networks running more than one protocol
A group of protocols that is intended to be used together is called a protocol suite
Most popular protocol suite is TCP/IP
Others: IPX/SPX, NetBIOS, and AppleTalk
Network Protocols Defined Demo
Understanding Network Protocols Demo
Transport Protocols Demo

5. Characteristics of TCP/IP (Transmission Control Protocol/Internet Protocol)
TCP/IP is not one protocol but a suite of specialized protocols called subprotocols.
Subprotocols include TCP, IP, UDP, ARP, ICMP, IGMP etc.
Developed by US Department of Defense
ARPANET (1960s)
Internet precursor
Advantages of TCP/IP
Open nature
Costs nothing to use
Flexible
Runs on virtually any platform
Connects dissimilar operating systems and devices
Routable
Transmissions carry Network layer addressing information
Suitable for large networks
Introduction Demo
Overview Demo
TCP IP Basics Demo

6. TCP/IP Compared to the OSI Model
The TCP/IP suite of protocols can be divided into four layers that roughly correspond to the seven layers of the OSI Model.
■ Application layer — The Application layer corresponds to the Session, Presentation, and Application layers of the OSI model. Applications gain access to the network through this layer, via protocols such as the File Transfer Protocol (FTP), Trivial File Transfer Protocol (TFTP), Hypertext Transfer Protocol (HTTP), Simple Mail Transfer Protocol (SMTP), and Dynamic Host Configuration Protocol (DHCP).
■ Transport layer — This layer comparable to the Transport layer of the OSI model and contains the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), which provide flow control, error checking, and sequencing. All service requests use one of these protocols.
■ Internet layer — This layer is comparable to the Network layer of the OSI model contains the Internet Protocol (IP), Internet Control Message Protocol (ICMP), Internet Group Message Protocol (IGMP), and Address Resolution Protocol (ARP). These protocols handle message routing and host address resolution.
■ Network access layer (or Link layer) — This layer corresponds to the functions of the Physical and Data Link layers of the OSI mode and is responsible for describing the physical layout of the network and how messages are formatted and transmitted to the network wire.
The TCP/IP Model (5:00)
   TCP/IP and OSI Models Demo 

7. The TCP/IP Suite Demo continued
The TCP/IP model compared with the OSI model
The TCP/IP Suite Demo continued
The TCP/IP Suite Demo
The TCP/IP Suite Demo continued

8. The TCP/IP Core Protocols
TCP/IP suite subprotocols
Operate in Transport or Network layers of OSI model
Provide basic services to protocols in other layers
Most significant protocols in TCP/IP suite
TCP IP
TCP/IP Suite Basics Demo
Networking Protocols (6:17)

9. TCP (Transmission Control Protocol)
Transport layer protocol that operates host to host.
Provides reliable data delivery services
Connection-oriented subprotocol
Establish connection before transmitting
Uses sequencing and acknowledgements
Provides flow control
TCP segment format
Encapsulated by IP packet in Network layer
Becomes IP packet’s “data”
Understanding TCP Demo

10. A TCP segment Transmission Control Protocol Demo
Connection Controls and Windowing Demo

11. TCP (cont’d.)
The TCP three-way handshake is the process used to establish a TCP session.
The steps to a TCP three-way handshake process are:
A host sends a SYN packet to the target host.
The target host responds to the original host with a SYN ACK packet.
The host responds to the target host with an ACK packet.
Establishing a TCP connection

12. UDP (User Datagram Protocol)
Transport layer protocol
Provides unreliable data delivery services
Connectionless transport service
No assurance packets received in correct sequence
No guarantee packets received at all
Best effort delivery
No error checking, sequencing
Lacks sophistication
More efficient than TCP
Useful when large amounts of data need to be transferred quickly such as with live audio and video transmissions over the Internet.
Understanding UPD Demo

13. UDP (User Datagram Protocol)
A UDP segment

14. IP (Internet Protocol)
Understanding IP Demo
Network layer protocol
How and where data delivered, including:
Data’s source and destination addresses
Addressing schemes: uses an IP address, such as and a Subnet Mask such as
Enables TCP/IP to internetwork
Traverse more than one LAN segment
More than one network type through router
Routing: Statically and Dynamically via many routing protocols; OSPF, BGP, RIP and EIGRP
Network layer data formed into packets
IP packet
Data envelope that contains information for routers to transfer data between different LAN segments
Unreliable, connectionless protocol
Relies on upper layer protocols like TCP to ensure delivery and connection orientation
Internet Protocol Demo
TCP/IP Demo Pt.2

15. IP Packet IP datagram: packet, in context of TCP/IP Envelope for data
IP adds the following header fields to each packet:
Source IP Address
Destination IP Address
Protocol
Checksum
Time to Live (TTL)
An IPv4 packet

16. IGMP
Operates at the Network layer of the OSI model and is a protocol for defining host groups
Manages multicasting on networks running IPv4
Allows one node to send data to a defined group of nodes
Similar to broadcast transmission
All group members can receive broadcast messages intended for the group (called multicasts)
Multicast groups can be composed of devices within the same network or across networks (connected with a router)
Point-to-multipoint method
Used for Internet teleconferencing or videoconferencing
Understanding IGMP Demo

17. ARP (Address Resolution Protocol )
Network layer protocol used with IPv4 that provides IP address-to-MAC address name address resolution
Obtains MAC (physical) address of host or node
A host wishing to obtain a physical address broadcasts an ARP request onto the TCP/IP network. The host on the network that has the IP address in the request then replies with its physical hardware address.
Creates database that maps MAC to host’s IP address
ARP table (ARP Cache)
Table of recognized MAC-to-IP address mappings
Saved on computer’s hard disk
Increases efficiency
Contains dynamic and static entries
Understanding ARP Demo
ARP (4:02)

18. ICMP (Internet Control Message Protocol)
ICMP is commonly used for troubleshooting and information gathering. ICMP allows you to test the path (among other things). Ping and Tracert are two tools that can be used to test a path and they both use ICMP. ICMP packets will be able to help send information about errors, control, and other informational messages.
Network layer protocol
Reports on data delivery success/failure
Announces transmission failures to sender
Network congestion
Data fails to reach destination
Data discarded: TTL expired
ICMP cannot correct errors
Provides critical network problem troubleshooting information
ICMPv6 used with IPv6
Understanding ICMP Demo

19. Connectivity Parameters
The following table summarizes the configuration settings required to connect to a TCP/IP network.
Parameter
Purpose
IP address
The IP address Identifies both the logical host and the logical network addresses.
Each host on the entire network must have a unique IP address.
Two devices on the same subnet must have IP addresses with the same network portion of the address.
Two devices on the same subnet must have unique host portions of the IP address.
Do not use the first or the last host address on a subnet address range.
Subnet mask
The subnet mask identifies which portion of the IP address is the network address, and which portion is the host address. Two devices on the same subnet must be configured with the same subnet mask.
Default gateway
The default gateway identifies the router to which communications for remote networks are sent. The default gateway address is the IP address of the router interface on the same subnet as the local host. Without a default gateway set, most clients will be unable to communicate with hosts outside of the local subnet.
DNS server
The DNS server address identifies the DNS server that is used to resolve host names to IP addresses.
Host name
The host name identifies the logical name of the local system.

20. IP Addressing Overview
IP Addresses Demo
IP Addressing Demo Pt.1
IP Addressing Demo Pt.2

21. Addressing in TCP/IP Networks recognize two addresses
Logical (Network layer)
Physical (MAC, hardware) addresses
IP protocol handles logical addressing
Specific parameters
Unique 32-bit number
Divided into four octets (sets of eight bits) separated by periods
Example:
Network class determined from first octet
IP Address Demo
 What is an IP Address? Demo
Adding Protocols Demo

22. Binary and Dotted Decimal Notation
Common way of expressing IP addresses
Decimal number between 0 and 255 represents each octet
Period (dot) separates each decimal
Each number in dotted decimal address has binary equivalent
Convert each octet
Remove decimal points
Base 2 Numbering is Binary
Consists of ‘0’ and ‘1’. Bits are either “Off” (0) or “On” (1)
Computers like Binary!
IP Addresses are comprised of four 8 bit octets that are expressed as a decimal number between 0 and 255 separated by a period
Bit Value
Bit = =179
Binary Math (7:59)
A Binary Lesson Demo
Binary Addressing Demo
Solutions for Binary Demo

23. Binary to Decimal Conversions
Bit Number:
Binary Equiv:
Decimal Equiv:
Binary Number:
Decimal Equiv: =
157
1) Determine what decimal numbers in the table will create the number you want to make.
2) Enter a “1” under each value you must use. Enter a “0” for each value that is not used in the Binary Number line.
3) The resulting combination of 0’s and 1’s is the binary equivalent of the number.

24. Sample Binary to Decimal Conversion
Convert Decimal 5 to Binary
Bit Number:
Binary Equiv:
Decimal Equiv:
Binary Number:
4) Determine what decimal numbers in the table will create the decimal number 5 (4+1).
5) The resulting combination of is the binary equivalent of the decimal number 5.

25. Address Classes
There are three primary classes of network addresses: A, B, and C.
The actual class used is based on the size of the network.
An IP address is accompanied by a subnet mask.
Each address class has a different default subnet mask.
IP addresses are expressed in dotted-decimal format, such as
Each set of four dotted-decimal numbers represents eight bits of the binary address.
The addresses range from to , or, in decimal notation, from 0 to 255.
IP Address Classes Demo
IP Classes (9:52)
Address Classes Demo

26. Classful Addressing Adheres to network class distinctions
Only Class A, B, and C addresses are recognized
Network ID limited to first 8 bits in Class A, first 16 bits in Class B, and first 24 bits in Class C
Fixed network ID size ultimately limits number of hosts a network can include
First Octet
First Octet 128 – 191
First Octet
Components of an IP Address Demo

27. Classful Addressing
IPv4 addresses have a default class. The address class identifies the range of IPv4 addresses. The following table shows the default address class for each IPv4 address range.
Class
First Octet Range
Number of Networks
Maximum Addressable Hosts per Network A
1-126
126
( to )
16,777,214
( to ) B
16,384
( to )
65,534
( to ) C
2,097,152
( to )
254
( to )

28. Reserved Addresses
Certain types of IP addresses reserved for special functions
Network ID Cannot Be 127
127 is reserved for lookback functions
Network ID and Host ID Cannot Be 255 (All Bits Set to 1)
In broadcast addresses, octet(s) representing host information set to all 1s (255 in decimal notation)
255 is a broadcast address
Network ID and Host ID Cannot Be 0 (All Bits Set to 0)
In network IDs, bits for host information set to 0
0 means “this network only”
Host ID Must Be Unique to the Network
IP Address Rules Demo

29. Addressing in TCP/IP
ipconfig: Windows NT, XP, Vista, 2000, 2003, 2008 command to view IP information
Winipcfg: Win98, ME
ifconfig on Unix
and Linux
/all switch
Results of the ipconfig /all command on a Windows XP or Windows Vista workstation
Ipconfig Demo
IPConfig,Ifconfig, Winipcfg Demo

30. What Is a Subnet Mask?
In binary form, the subnet mask is always a series of 1's followed by a series of 0's (1's and 0's are never mixed in sequence in the mask). A simple mask might be
Distinguishes the Network ID from the Host ID
Combines with device IP address to mask the Network ID with all 1s
Informs network about segment, network where device attached
Used to specify whether the destination host is local or remote (ANDing)
Four octets (32 bits)
Expressed in binary or dotted decimal notation
Assigned same way as IP addresses
Manually or automatically (via DHCP)
Subnet Mask Demo
Subnet Masks Demo

31. Subnet Masks
Every device on TCP/IP-based network identified by subnet mask
32-bit number that, when combined with device’s IP address, informs rest of network about segment or network to which a device is attached
Subnetting, subdividing single class of networks into multiple, smaller logical networks or segments, depends on subnet masks to identify how a network is subdivided
Indicates where network information is located in an IP address
“1” bits indicate corresponding bits in IP address contain network information
“0” bits indicate corresponding bits in IP address contain host information
To calculate host’s network ID given IP address and subnet mask, perform ANDing
Anding IP Addresses Demo
Subnet Masks Demo
Solutions for Masks Demo

32. Default Subnet Masks (No Subnetting)
Address
Class
Bits Used for Subnet Mask
Dotted Decimal
Notation
Class A
Class B
Class C
Class B Example
IP Address
16.200
0.0
Subnet Mask
Network ID
y.z
Host ID
w.x.
16.200

33. IPv6 Addressing Composed of 128 bits Eight 16-bit fields
Typically represented in hexadecimal numbers
Separated by a colon
Example: FE22:00FF:002D:0000:0000:0000:3012:CCE3
Abbreviations for multiple fields with zero values
00FF can be abbreviated FF
0000 can be abbreviated 0
Multicast address
Used for transmitting data to many different devices simultaneously
Anycast address
Represents any one interface from a group of interfaces
Modern devices and operating systems can use both IPv4 and IPv6
Why IPv6? Demo
IPv4 and IPv6 (5:18)
IPv6 Basics Demo

34. ADDRESS ASSIGNMENT
Because IP addresses assigned to hosts must be unique, the use of IP addresses on the Internet is controlled by organizations that ensure that no two organizations are given the same range of IP addresses to assign to hosts.
The Internet Assigned Numbers Authority (IANA) manages the assignment of IP addresses on the Internet. IANA is operated by the Internet Corporation for Assigned Names and Numbers (ICANN).
IANA allocates blocks of IP addresses to Regional Internet Registries (RIRs). An RIR has authority for IP addresses in a specific region of the world.
An RIR assigns a block of addresses to Internet Service Providers (ISPs).
An ISP assigns one or more IP addresses to individual computers or organizations connected to the Internet.
On private networks IP addresses are assigned to computers either manually, called static addressing, or automatically through a DHCP server which is called dynamic address allocation.
Configure TCP/IP Demo
IP Address Assignment Demo Pt.1

35. DHCP (Dynamic Host Configuration Protocol)
Automatically assigns device a unique IP address
Application layer protocol
Reasons for implementing
Reduce time and planning for IP address management
Reduce potential for error in assigning IP addresses
Enable users to move workstations and printers
Make IP addressing transparent for mobile users
DHCP leasing process
Device borrows (leases) an IP address while attached to network
Lease time
Determined when client obtains IP address at log on
User may force lease termination
DHCP service configuration
Specify leased address range
Configure lease duration
Several steps to negotiate client’s first lease
Dynamic Addressing Demo
Dynamic Clients Demo

36. DHCP Leasing Process
Device borrows (leases) an IP address while attached to network
Lease time
Determined when client obtains IP address at log on
User may force lease termination
ipconfig /release
DHCP service configuration
Specify leased address range
Configure lease duration
Several steps to negotiate client’s first lease

37. DHCP Leasing Process
DHCP Addressing Overview (4:35)
The client goes through a four stage broadcast based process to obtain an IP Address lease from a DHCP server.
Step 1: Upon bootup the client sends out a DHCPDISCOVER packet in broadcast fashion to discover the identity and whereabouts of all DHCP servers on the broadcast segment.
Step 2: Upon receiving the broadcast any DHCP servers on that broadcast segment will respond with their own DHCPOFFER packet.
Step 3: The client will accept the first offer received and respond with a DHCPREQUEST broadcast. Other DHCP servers who have made an offer hear this broadcast and return their IP address to the pool.
Step 4: The chosen DHCP server responds with an DHCPACK confirming the clients acceptance of the IP lease along with additional information such as subnet mask, default gateway and DNS server.

38. DHCP Leasing Process DHCPOFFER BROADCAST DHCPDISCOVER BROADCAST
DHCPACK
BROADCAST
DHCPREQUEST
BROADCAST
DHCP Lease Process Demo
DHCP in a Routed Environment Demo

39. IP Lease Renewal
DHCP Leases (4:24)

40. Terminating a DHCP Lease
Lease expiration
Automatic
Established in server configuration
Manually terminated at any time
Client’s TCP/IP configuration
Server’s DHCP configuration
Circumstances requiring lease termination
DHCP server fails and replaced
Windows: release of TCP/IP settings
DHCP services run on several server types
Installation and configurations vary

41. Private Addresses Private addresses
Allow hosts in organization to communicate across internal network
Cannot be routed on public network
Specific IPv4 address ranges reserved for private addresses
Addresses: 16,777,216
Addresses: 1,048,576
Addresses: 65,536
The private addressing works well for allowing computers to access resources inside the private network only
Routers inside the private network can route traffic between private addresses with no trouble.
To access the Internet, or a public network, computers have to have a public address. This is where Network Address Translation (NAT) comes into play.
Routers on the Internet will not accept IP addresses in a private IP address range
Special Addresses Demo

42. Link-Local Addresses APIPA (Automatic Private IP Addressing)
Provisional address
Capable of data transfer only on local network segment
APIPA is a Microsoft implementation of automatic IP address assignment without a DHCP server. Using APIPA, hosts assign themselves an IP address on the network (mask of ). With APIPA:
The host is configured to obtain IP information from a DHCP server (this is the default configuration).
If a DHCP server can't be contacted, the host uses APIPA to assign itself an IP address.
The host only configures the IP address and mask. It does not assign itself the default gateway and DNS server addresses. For this reason, APIPA can only be used on a single subnet.
Disadvantage
Computer only communicates with other nodes using addresses in APIPA range
APIPA (3:42)
IP Address Assignment Demo Pt.2

43. Static (manual) Assignment
Using static addressing, IP configuration information must be manually configured on each host. Use static addressing:
On networks with a very small number of hosts.
On networks that do not change often or that will not grow.
To permanently assign IP addresses to hosts that must always have the same address (such as printers, servers, or routers).
For hosts that cannot accept an IP address from DHCP.
To reduce DHCP-related traffic.
Static addressing is very susceptible to configuration errors and duplicate IP address configuration errors.
Static addressing disables both APIPA and DHCP capabilities on the host.
Static Addressing Demo
Static Clients Demo

44. Ports and Sockets
Ports are logical connections, provided by the TCP or UDP protocols at the Transport layer, for use by protocols in the upper layers of the OSI model. TCP/IP uses port numbers stored in the header of a packet to determine what protocol incoming traffic should be directed to.
Every process on a machine assigned a port number 0 to 65535
Process’s port number plus host machine’s IP address equals process’s socket Example: :53
Ensures data transmitted to correct application
Well Known Ports: in range 0 to 1023
Assigned to processes that only the OS or system administrator can access
Registered Ports: in range 1024 to 49151
Accessible to network users and processes that do not have special administrative privileges
Dynamic and/or Private Ports: in range through 65535
Open for use without restriction
Understanding Port Numbers Demo
Common TCP and UDP Ports (8:09)

45. Sockets and Ports Well Known Port Numbers Demo
Commonly used TCP/IP port numbers

46. Name Resolution Overview
Name Resolution Overview Demo
NetBIOS Name Resolution Demo
Resolving a Host Name Demo
DHCP/ DNS/WINS Servers Demo

47. Host Names and DNS (Domain Name System)
TCP/IP addressing
Long, complicated numbers
Good for computers
People remember words better
Internet authorities established Internet node naming system
Host
Internet device
Host name
Name describing device
Every host can take a host name
Host Naming Demo

48. Domain Names What is DNS? Demo Domain
Group of computers belonging to same organization
Share common part of IP address
Domain name
Identifies domain (loc.gov)
Associated with company, university, government organization
Fully qualified host name (blogs.loc.gov)
Local host name plus domain name
Label (character string)
Separated by dots
Represents level in domain naming hierarchy
Example:
Top-level domain (TLD): com
Second-level domain: google
Third-level domain: www
Second-level domain
May contain multiple third-level domains
ICANN established domain naming conventions
Domain names must be registered with an Internet naming authority that works on behalf of ICANN
What is DNS? Demo

49. Domain Names (cont’d.) ICANN approved over 240 country codes
Host and domain names restrictions
Any alphanumeric combination up to 253 characters
Include hyphens, underscores, periods in name
No other special characters
Structure of DNS Demo

50. Host Files ARPAnet used HOSTS.TXT file
Associated host names with IP addresses
Host matched by one line
Identifies host’s name, IP address
Alias provides nickname
UNIX-/Linux-based computer
Host file called hosts, located in the /etc directory
Windows computer
Host file called hosts
Located in Windows\system32\drivers\etc folder
Host Name Resolution Demo

51. DNS (Domain Name System)
An Overview of DNS (8:12)
Hierarchical method of associating domain names with IP addresses
Refers to Application layer service that accomplishes association and organized system of computers and databases making association possible
DNS redundancy
Many computers across globe related in hierarchical manner
Root servers
13 computers (ultimate authorities)
Three components
Resolvers
Any hosts on Internet needing to look up domain name information
Name servers (DNS servers)
Databases of associated names, IP addresses
Provide information to resolvers on request
Namespace
Abstract database of Internet IP addresses, associated names
Describes how name servers of the world share DNS information
Root Domain Name Servers Demo
The DNS Namespace Demo

52. DNS Resource Records DNS Records (9:05) DNS Records Demo
Entries for hostnames, IP addresses, and other information in the zone database are stored in records. Each host has at least one record in the DNS database that maps the hostname to the IP address. The following table lists common resource records.
The A record maps an IPv4 (32-bit) DNS host name to an IP address. This is the most common resource record type.
The AAAA record maps an IPv6 (128-bit) DNS host name to an IP address.
The CNAME record provides alternate names (or aliases) to hosts that already have a host record. Using a single A record with multiple CNAME records means that when the IP address changes, only the one A record needs to be modified.
The MX record identifies servers that can be used to deliver .
The PTR record maps an IP address to a host name (i.e. "points" to an A record).
DNS Records (9:05)
DNS Records Demo

53. Domain Name Space
The Domain Name System (DNS) is a hierarchical, distributed database that maps logical host names to IP addresses. The DNS hierarchy is made up of the following components:
. (dot) domain (also called the root domain)
Top Level Domains (TLDs) such as .com, .edu, .gov
Additional domains such as yahoo.com, microsoft.com, etc.
Hosts
The fully-qualified domain name (FQDN) includes the host name and all domain names, separated by periods. The final period (for the root domain) is often omitted and implied.

54. DNS Resolution Process
The client looks in its local cache to see if it has recently resolved the host name.
If the information is not in the cache, it checks the Hosts file.
If the IP address is not found, the host contacts its local DNS server. If the local DNS server can't be contacted, it continues contacting additional DNS servers until one responds.
The client sends the name information to the DNS server.
The DNS server then checks its cache and Hosts file. If the information is not found, the DNS server checks any zone files that it holds for the requested name.
If the DNS server can't find the name in its zones, it forwards the request to a root zone server. This server returns the IP address of a DNS server that has information for the corresponding top-level domain (such as .com).
The local DNS server then requests the information from the top-level domain server. This server returns the address of a DNS server with the information for the next highest domain (Microsoft).
The local DNS server then requests the information from the Microsoft DNS server which holds the necessary information. This server returns the address of the requested host name.
The local DNS server places the information in its cache and returns the IP address to the client.
The client host also places the information in its cache and uses the IP address to contact the desired destination device.
Resolving
Name Resolution Demo

55. DDNS (Dynamic DNS)
Dynamic DNS (DDNS) enables clients or the DHCP server to update records in the zone database.
Without dynamic updates, all A (host) and PTR (pointer) records must be configured manually. With dynamic updates, records are created and deleted automatically.
Dynamic DNS is required to support Active Directory.
A dynamic update occurs when a client modifies its corresponding resource record on the DNS server.
Dynamic updates occur when:
A network connection's IP address is added, deleted, or changed.
The DHCP server changes or renews an IP address lease.
The client's DNS information is manually changed using ipconfig /registerdns.
The client boots.
A server is promoted to a domain controller.
Dynamic DNS (4:26)
Integrating DHCP DDNS Demo

56. Application Layer Protocols
Management Protocols (10:51)
Application Protocols (9:36)
Work over TCP or UDP plus IP
Translate user requests into format readable by network
HTTP
HTTP is used by Web browsers and Web servers to exchange files (such as Web pages) through the World Wide Web and intranets
HTTPS is a secure form of HTTP that uses SSL to encrypt data before it is transmitted.
DHCP
DHCP is a method for automatically assigning addresses and other configuration parameters to network hosts.
Understanding HTTP Demo
Other Protocols Built on TCP/IP Demo

57. Telnet Terminal emulation protocol Log on to remote hosts
Using TCP/IP protocol suite
TCP connection established
Keystrokes on user’s machine act like keystrokes on remotely connected machine
Often connects two dissimilar systems
Can control remote host
Drawback
Notoriously insecure
The Concept of Telnet Demo

58. FTP (File Transfer Protocol)
FTP provides a generic method of transferring files
Send and receive files via TCP/IP
FTP can transfer both binary and text files, including HTML, to another host
Host running FTP server portion
Accepts commands from host running FTP client
FTP commands
Operating system’s command prompt
No special client software required
FTP hosts allow anonymous logons
Secure FTP (SFTP)
More secure version of FTP
SFTP uses Secure Shell (SSH) to secure data transfers.
SSH ensures that SFTP transmissions use encrypted commands and data which prevent data from being transmitted over the network in clear text.
Understanding FTP & TFTP Demo
SFTP Demo

59. TFTP (Trivial File Transfer Protocol)
Enables file transfers between computers
Simpler (more trivial) than FTP
TFTP is faster than FTP, but might be subject to file errors
TFTP relies on Transport layer UDP
Connectionless
No error correction and does not guarantee reliable data delivery
No ID or password required
Security risk
No directory browsing allowed
Useful to load data, programs on diskless workstation
Often used when transferring files such as video, audio, or images

60. NTP (Network Time Protocol)
NTP is used to communicate time synchronization information between systems on a network
Depends on UDP Transport layer services
Benefits from UDP’s quick, connectionless nature
Time sensitive
Cannot wait for error checking
Time synchronization importance
Routing
Time-stamped security methods
Maintaining accuracy, consistency between multiple storage systems

61. PING (Packet Internet Groper)
Provides verification
TCP/IP installed, bound to NIC, configured correctly, communicating with network
Host responding
Uses ICMP services
Send echo request and echo reply messages
Determine IP address validity
Ping IP address or host name
Ping loopback address:
Determine if workstation’s TCP/IP services running
Ping (5:16)

62. PING (cont’d.)
Operating system determines PING command options, switches, syntax
Ping Demo
Output from successful and unsuccessful PING

63. Summary
Protocols define the standards for communication between nodes on a network
TCP/IP is most popular protocol suite, because of its low cost, open nature, ability to communicate between dissimilar platforms, and routability
TCP provides reliability through checksum, flow control, and sequencing information
IP provides information about how and where data should be delivered
Every IP address contains two types of information: network and host

64. Summary (continued)
Subnetting is implemented to control network traffic and conserve a limited number of IP addresses
Dynamic IP address assignment can be achieved using BOOTP or the more sophisticated DHCP
A socket is a logical address assigned to a specific process running on a host
IPv6 provides several other benefits over IPv4
A domain is a group of hosts that share a domain name and have part of their IP addresses in common
DNS is a hierarchical way of tracking domain names and their addresses

65. The End