The document discusses domains in information technology and computer networking. It defines domains as a group of networked computers that share a common communications address. It describes domain name systems which allow computers on the internet to be identified with alphanumeric names instead of IP addresses. It also discusses how domains are used in Windows networks to group computers and users together and centrally manage authentication, permissions and resources.

1. COP 4910 Frontiers in Information Technology Lecture 6 Domains Hal Stringer

2. Today’s Agenda Turn in first Mini-Report Next MR due Tuesday of Next Week What about the other MRs Domains Topic for Next Tuesday’s Lecture?

3. Mini-Report Overview Information Posted on Website Background Information Technology Overview Business Issues Technical Details Implementation Issues Questions?

4. What is a Domain? Per www.dictionary.com A territory over which rule or control is exercised. A sphere of activity, concern, or function; a field: the domain of history. Computer Science . A group of networked computers that share a common communications address. Two common “domains” in IT: Domain Name for internet navigation Windows Domain for LAN or WAN networking

5. Internet Domain Names All computers connected to the Internet have a unique IP address. Used by TCP/IP protocols to route packets IP addresses are difficult to remember DNS or Domain Name System developed to provide mapping between alphanumeric mnemonic names and IP addresses. Real time mapping of names to IP addresses is called “name resolution” Internet Corporation for Assigned Names and Numbers (ICANN) administers domain names and IP addresses to insure universal resolvability.

6. Domain Name System All names form a hierarchy Top Level Domains (org, .com, .info, .us, etc.) 2 nd Level Domain Name (abcwidget, cnn, msnbc, etc.) Host Names (www, mail, ftp, corporate, west, etc.) Example: www.abcwidget.com 13 root name servers contain IP addresses of all TLD registries (master name servers) Each master name server has IP addresses for all second level domain name servers Each name server has records for all hosts associated with a given second level domain name Local name resolvers cache information already received from root, master, or other name servers. Maintained by ISPs or by Corporate Network Administrators

7. Setting Up a Domain on the Internet Purchase domain name (e.g., abcwidget.com) from ICANN registrar Lease web server(s) from ISP ISP provides IP addresses for web server(s) Determine location (IP address) for name server Give to registrar so record can be created in master name server Enter records for all hosts with appropriate IP addresses Wait for changes to propagate

8. Domains for Computers & LANs Early computers had no domains All users defined in a computer Permissions determined by administrator at user/group level Each computer administered separately IBM System Network Architecture “Domain” consists of all Physical Units (FEPs, CCs, terminals) and Logical Units (Users, Applications) connected to single Host Processor Introduction of PCs Windows for Workgroup (P2P) Novell Netware (Client/Server)

9. Windows NT Domains Each Windows NT Workstation has its own list of users and associated permissions User Name & Password required to use the workstation NT workstations are collected into a domain with access to a single account login database. Authorized user can log in at any workstation in domain. Domain controller maintains account database User authentication performed by DC on behalf of workstation DC usually a separate NT server with backup DCs for disaster and load balancing Trust relationships allow users to connect to hosts/services in a different domain

10. Windows 2000 3 Versions: Professional, Server, Advanced Server Server versions provide services including: User Login and Authentication Storage Management & Clustering File Server Print Server Web Server Networking (DHCP, DNS, WINS) Terminal Services Support for optional services Exchange Server, Sequel Server

11. Active Directory One of biggest changes from NT Server Provides both a Namespace and Directory Structure for domains, servers, workstations, administrators, users and other objects across a network Combines X.500 naming standards, Internet DNS and LDAP (Lightweight directory access protocol) Provides single point of administration for all resources on network All domain controllers are peers. Changes are replicated to all other DCs in the network. Based on hierarchical (trees and subtrees) object model (identities, attributes, containers) with delegation and inheritance.

12. Namespace Setting up a Namespace Tree: Single contiguous namespace descending from single root node. Good for cohesive, top-down organizations Forest: Collection of equal trees with no single root Good for larger enterprises with multiple lines of business Naming Convention: How leafs & nodes are identified Organizational - based on departments or functions Geographical – based on territory Name Resolution for internal and external users Single NS ( www.abcwidget.com , corp.abcwidget.com) Separate NS ( www.abcwidget.com , corp.abc.com)

13. Domain Planning Domain structure follows namespace Each branch of namespace can be a domain or organization unit (OU) Domain: Core unit of Active Directory for administration & replication Uniform security policy applies to entire domain. All network objects exist as part of a domain Managed from one or more Domain Controllers OU: Subset of domain derived from a subtree of the namespace. Allows delegation of administrative rights to other users within the OU with MMCs.

14. Domain Implementation Install Windows 2000 Server Configure Server First server on network must be a domain controller and include: Active Directory Service DHCP Service DNS Service WINS Service (optional) Additional servers can be added as member servers or domain controllers. Can install DHCP, DNS or WINS on additional DCs for backup and recovery Create users, computers, groups or shared folders/printers as needed.