NetworkingEvolution of the Internet1958: in response to Sputnik the Advanced Research Projects Agency (ARPA) is created1969: ARPANET commissioned by DoDarchitecture consisted of Interface Message Processors (IMPs)first four IMPS installed early 70s: Term Internet was used over ARPANET1NetworkingEvolution of the Internet, cont.early 70s: IP protocol moved data from one site to another, but without guaranteethen TCP (transmission control protocol) was added on top of IP to establish “reliability”UDP (user datagram protocol) added low overhead method, but it does not guarantee message arrivalIP addresses had to be uniquely defined for each Network Information Center (NIC)2NetworkingEvolution of the Internet, cont.classes of networks were defined, e.g., Class A or our Bnow internet applications could be built, e.g., telnet and ftp1980s: new hosts were added at a rate that required daily network host table modificationseach ARPANET site had to download new host tables each day to stay up-to-datethe number of available hostnames was dwindling, since each hostname in the entire network had to be unique 3NetworkingEvolution of the Internet, cont.Domain Name Service (DNS) DNS and BIND (Berkeley Internet Name Deamon) proposed hierarchy of domain naming of network hostsmethod for providing address information to anyone who requested it4NetworkingEvolution of the Internet, cont.Common top-level domain namesbiz: businesscom: commercialedu: educationalgov: governmentalinfo: unrestricted (i.e., anything)mil: militarynet: network service providerorg: nonprofit organizationXX: two-letter country code5NetworkingCommand hostUtility: host [ hostname | IPaddress ]contacts the local Name Service and requests the IP address for a given hostname. It can also do a reverse lookup, where by specifying an IP address you receive the hostname for that address.6NetworkingCommand host-bash-3.2$ host www.ebay.comwww.ebay.com is an alias for hp-core.ebay.com.hp-core.ebay.com has address 66.211.181.15hp-core.ebay.com has address 66.211.181.19hp-core.ebay.com has address 66.135.200.27hp-core.ebay.com has address 66.135.200.145hp-core.ebay.com has address 66.211.181.11-bash-3.2$ -bash-3.2$ host 66.211.181.1515.181.211.66.in-addr.arpa domain name pointer hp-core.ebay.com.-bash-3.2$ 7NetworkingThe Web of the 90smillions of users and no real app until...Mosaic, the first browser came outcould do things without having to use e.g., telnet or ftpMosaic could display pages of information textually and graphicallyMosaic used a page description language called HyperText Markup Language (HTML)the hyperlink was most revolutionary aspectnow one could “navigate”but: each participating site had to set up servers to provide this info8NetworkingThe Web of the 90sSome of the people involved in the early releases of Mosaic later formed Netscape Communications Inc.The Web vs the Internet“Did you mean the Internet of the web of information available on the Internet?”Internet: the networked infrastructureWeb: the web of information (HTML documents) connected to others (via hyperlinks)9NetworkingSecurity, or “lack thereof”Internet security is a huge topicInternet was not designed with electronic commerce in mindMajor risks (as per our book)information copyinginformation modificationimpersonationdenial of service10NetworkingSecurity, or “lack thereof”Common definition in terms ofconfidentialityintegrityavailabilityauthenticitynon-repudiation11NetworkingOther issuesCopyrightCensorshipMisinformationAcceptable
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