More TCP/IP Protocols

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26 Οκτ 2013 (πριν από 3 χρόνια και 8 μήνες)

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More TCP/IP Protocols

Chapter 6 Lecture 2

HTTP


Hypertext Transfer Protocol


Allows text, graphics, multimedia to be
downloaded from an web server


HTTP clients = web browsers


Uses UDP


URL


uniform resource locator


HTML


scripting language for web
pages


HTTPS


Hypertext Transfer Protocol Secure


Employs secure socket layers


SSL


an added protocol layer between HTTP and
the Transport layer


Encrypts information transmitted between clients
(Netscape and Microsoft) and web servers.


Web servers


Apache


Microsoft IIS


Telnet


Terminal emulator


Sessions opened on a remote host


Allows user to access applications and
data on the host computer. Use the
host for processing.


Authentication required


Uses TCP.

ICMP


Internet Control Message Protocol


Message control and error reporting
between host and server


Works with IP


Tracert and Ping are two of the most
commonly used ICMP network
management tools.


ARP


Address Resolution Protocol


Allows a device that knows a
destination’s IP address but doesn’t
know the destination’s MAC address to
find it.

NTP


Network Time Protocol


Synchronize computer clock times of all
computers in the LAN.

Network Services


DHCP/BOOTP


DNS


NAT/ICS


WINS


SNMP

DHCP


Dynamic Host Configuration Protocol


A server is set up with this service to
dynamically assign IP addresses to hosts.


Scope


the range of IP addresses from
which the DHCP server assigns addresses


Lease


the amount of time which the server
assigns IP address to the host


Reservation


an IP address is reserved for a
particular host


Not platform dependent

DHCP Advantages &
Disadvantages


Eliminates manual configuration for each host


Eliminates duplicate IP addresses (human
error)


Eliminates need to reconfigure if the host is
moved


Increases traffic (disadvantage)


DHCP server must be installed and
configured. (disadvantage)



BOOTP


Older protocol to automatically assign
IP addresses to hosts.


DHCP was modeled after BOOTP.

DNS


Domain Name Service


Requires a server configured as a DNS server


Resolves hostnames to IP addresses


Example:
www.yorktech.com

is 172.16.2.11


HOST file


contained names and aliases matched to IP
addresses


manually configured


DDNS


allows automatic additions of host
names to IP addresses


Platform independent

DNS Namespace


Hierarchical structure with logical
divisions of domains

EDU

COM

GOV

JP

Winthrop.edu

IBM.COM

DOC.gov

Google.co.jp

NAT


Network Address Translation


Allows many computers to connect to the
Internet through one connection


Static: server configured with an IP address


External IP address(es) may be within the official
network IP address


Internal IP addresses used by nodes may be
private addresses


Dynamic: server assigns IP addresses from a
range to be used by hosts as they request
web access

ICS


Windows version of NAT


Lacks security


SNMP


Simple Network Management Protocol


Facilitates network management


it isn’t a
network management system (NMS) itself


NMS is a special software


Requires two modes


Manager software


Agent software


Ability to monitor and manage hardware over
a WAN

IP Version 6


Uses 128
-
bit addresses


Greater number of IP addresses.


Eight octets in Hexadecimal format


Example:
52DF:7E22:63F2:21AA:CBD4:D77e:CC21:554F


Other features


Smaller headers (lower overhead)


Packet labeling (prioritization)


Improved authenticity/security