Network Protocols
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Transcript Network Protocols
Network Protocols
Why Protocols?
Rules
and procedures to govern
communication
Some for transferring data
Some for route discovery
TCP/IP
Suite
of Protocols to define communication
Application – client functionality
Transport - moving data
Network – tasks for moving data
Steps –Sending
Protocol
responsible for breaking data into
smaller parts called packets
Network address is attached to packet
Data prepared for transmission and sent
through NIC
Steps - Receiving
Data
received, taken off network through
NIC
Address information stripped
Data packets are resembles
Packets are then sent to application for
use.
Common Protocols
TCP
FTP
UDP
TCP/IP
DHCP
TFTP
DNS
HTTP
ARP
SIP
RTP
SSH
POP3
NTP
IMAP4
TELNET
SMTP
SNMP
ICMP
IGMP
TLS
TCP
Transmission
Control Protocol
Connection oriented – establishes a
manually acknowledged session between
two hosts.
Provides reliability to IP
Flow control, sequencing, and error
detection and correction.
Transport layer
TCP Connection
Sends
SYN to target host
Target opens connection and sends ACK
Originated host sends ACK ready to
transfer data
Called three-way handshake
UDP
User
Datagram Protocol
No guarantee delivery
“fire and forget”
Uses IP
Transport layer
Lower overhead – low bandwidth
FTP
File
Transfer Protocol
Uploading and downloading of files
Uses TCP as a transport protocol
Used to transfer files over the LAN
Popular to distribute files over the internet
Application
layer
Common FTP commands
know
SSH
Secure
Shell
Alternative to telnet
Provides security and encryption
Allows sessions to be opened on a remote
host
SFTP
Secure
File Transfer Protocol
Authentication between sender and
receiver
Encryption – if packets copied remain
hidden
Implemented though client and server
software
Allows for securely uploading and
downloading files to and from remote host
TFTP
Trivial
File Transfer Protocol
File transfer
Not the same file security and functionality
as FTP
Simple downloads – firmware
No directory navigation
Uses UDP
Application layer
SMTP
Simple
Mail Transfer Protocol
How mail is sent/transported through the
network
TCP
Can be used to send and receive mail
authentication
HTTP
Hypertext
Transfer Protocol
Uses TCP
Allows text, graphics, multimedia and
other material to be downloaded
Requests sent in clear text
HTTPS
Hypertext
Transfer Protocol Secure
SSL – encrypts
Both the client and server must support
POP3/IMAP4
Post
Office Protocol 3/ Internet Message
Access Protocol
Can download email but not send
Passwords transferred in clear text
Telnet
Virtual
terminal protocol
Allows session to be opened and
commands executed
Used to access routers and other network
devices
Not secure
ICMP
Internet
Control Message Protocol
Works with the IP layer to provide error
checking and reporting
Tools to provide best-delivery
PING
Used for error reporting, flow control, and
route testing
ARP
Address
Resolution Protocol
Resolving IP addresses to MAC
addresses
RARP
Reverse ARP
Resolves
MAC to IP addresses
Reveres lookups in DNS
Network Time Protocol NTP
Facilitates
the communication of time
between systems
Important for email and directory services
Network News Transfer Protocol
NNTP
Posting
and retrieval of messages
Application layer
Secure Copy Protocol SCP
Secure
means of copying files
Encrypts data
More secure then RCP
Lightweight Directory Access
Protocol LDAP
Access
and query directory services
NDS and ADS
Internet Group Management
Protocol IGMP
Manages
multicast
Used to register and discover devices
Routers and videoconferencing clients
Domain Name Service DNS
Resolves
host names to IP addresses
Used to use txt file hosts
WINS
On
windows allows NetBIOS names to be
resolved to IP addresses.
If no WINS server use LMHOSTS file
Simple Network Management
Protocol SNMP
Network
management of devices
Dynamic Host Configuration
Protocol DHCP
Automatically
assigns IP addresses
Allows a range of IP addresses to be
defined
Clients ask the server for and address
Lease - scope
Transport Layer Security TLS
Ensure
privacy between client/server apps
Session Initiation Protocol SIP
VOIP
Establish
and maintain multimedia
sessions
Internet telephone calls
Uses
TCP or UDP
Application layer
Real Time Transport Protocol
RTP
Transport
of real-time data
Does not guarantee delivery
Transport Layer
Ports
Each
protocol needs a port to access and
leave the system
Ports
TCP/IP
has 65,535 ports
Well known – 0-1023
Registered ports – 1024-49151
Used by apps or services
Dynamic
or private – 49152 – 65353
Can be used for any service or app
– 20 – TCP
FTP – 21 TCP
SSH – 22 TCP
Telnet – 23 – TCP
SMTP – 25 – TCP
DNS – 53 – UDP/TCP
TFTP – 69 – UDP
HTTP – 80 – TCP/UDP
POP3 – 110 – TCP
FTP
– 119 – TCP
NTP – 123 – TCP
IMAP4 – 143 – TCP
SNMP – 161- UDP
HTTPS – 443 – TCP
DHCP – 67 - UDP
NNTP
IP Address
Consists
of a series of 32 binary bits
Grouped into four 8-bit bytes
Called and octet
Presented in decimal value
Composed
of two parts
First part – network
Second part - host
Example
192.168.18.57
First three octets are network
• 192.168.18
Last octet identifies the host
• 57
Address Ranges
Class
Address Range
A
10.0.0.0-10.255.255.255
255.0.0.0
B
172.16.0.0-172.31.255.255
255.255.0.0
C
192.168.0.0-192.168.255.255 255.255.255.0
Default Subnet
Mask
Need to Know
169.254.0.0-
no DHCP server to give
address
127 loopback
Class
IP
addresses are divided into 5 classes
Class A – large networks
Class B – medium sized networks –
universities
Class C – small networks – ISP’s for
customers
Class D – multicasting
Class E - testing
Subnet Mask
Network
portion of the address
Hosts on a LAN use the same subnet
mask
Subnet Mask cont
Class A –
255.0.0.0
Class B – 255.255.0.0
Class C – 255.255.255.0