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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.
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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