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COMP1321 Digital Infrastructure. Richard Henson February 2014. Week 15: Active Directory and Enterprise Networks. Objectives: Explain the importance of X500 compliance for Internet-based database Explain how Active Directory can control login and access to network resources
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COMP1321Digital Infrastructure Richard Henson February2014
Week 15: Active Directory and Enterprise Networks • Objectives: • Explain the importance of X500 compliance for Internet-based database • Explain how Active Directory can control login and access to network resources • Explain how Active directory can provide trust across multiple domains
More about Active Directory • An LDAP network-wide directory service for providing paths to files and services • available from Windows 2000 onwards • of limited use on networks with NT v4 clients • All domain controllers contribute to, share, and are part of the Active Directory system • data on network resources, services & users all stored in a single file • ntds.dit • tools available for AD system management • e.g. ntdsutil
X500 compliance • Many rules laid doown for applications and data structures held on Internet • Database: object-oriented (X500 compliant) • Query of database through LDAP (lightweight database access protocol)
What is Active Directory? • Object-oriented database (compliant with X500 standard) • hierarchy of data objects (& their properties) • domain controllers • computers • users & groups of users • network resources
Backing up the Database • Goes without saying that the loss of Active Directory will be bad for the network • people won’t even be able to log on! • Should be backed up… regularly! • Best way to do this is on another computer…
Fault Tolerance • General engineering principle… • if it can go wrong… it will! • To maintain availability for users, the whole domain controller should be backed up! • active directory designed as a distributed database that backs up to a reserve domain controller • backup domain controller software set up using same active directory wizard
Fault Tolerance (hardware fault) • E.g. Hard disks • can crash or become corrupt • System needed for a backup to take over “seamlessly” • i.e. without the user noticing… • Achieved by disk mirroring • exact copy available to take over at a moment’s notice
Domain Trust • This allows users on one domain to log onto resources on another domain • Trusts can be one or two-way Domain A Domain B
Enterprise Structure of Active Directory • A hierarchical system of organisational data objects • i.e. domains, • A Tree can be • a single domain • group of domains
Domain Trees & Forests • Active Directory provides “trust” between the databases of domains that are linked in this way • A “Tree” is the domains and links between them • A “Forest” contains data needed to connect all objects in the tree: • domain objects in the tree are logically linked together in the forest and their users can “trust” each other
Active Directory and Users • Active directory allows set up and management of domain users • Can also define domain groups, and allow domain users to become part of domain groups • aids administration • policy file can be set up • interacts with user machines registry during login • controls user desktop
Organisations, Organisational Units, and Domains • An organisation may: • have several locations • have several functions in same location • Alternative to multiple domains… • organisational units • group policy can be applied selectively
WINS (Windows Internet Names Service) • Used on earlier Windows TCP/IP networks to enable computer devices to communicate using IP • manages a dynamic database of IP addresses and local network (NetBIOS) names • clients request IP addresses for particular NetBIOS names • WINS server provides that information
Active Directory and DNS • In Active directory, each domain in the tree has a unique DNS identity • therefore a unique IP address… • can cause confusion when setting up domain structure!! • Also, each device within a domain can also made use of DNS, via its IP address… • no need for WINS…
Microsoft TCP/IP stack • Differs from UNIX TCP/IP (e.g. no FTP, SMTP or Telnet) • DNS is available as a network service • Application layer components: • Windows sockets - to interface with sockets-based applications • NetBT - to interface with NetBIOS applications • SNMP, TCP, UDP, IP as with Unix protocol stack
Configuring TCP/IP on Windows • Requires local administrator access!! • 1. Find “Local Area Connection”: • either through Control Panel/Network & Dial up connections • or by right-clicking on Network Places and choosing Properties • 2. Right click on Local Area connection • 3. Click on “properties”
TCP/IP Configuration (2) • Locate and double-click TCP/IP • If DHCP (dynamic host configuration protocol) is running, IP addressing is dealt with automatically by the DHCP server • Otherwise, three IP addresses need to be added: • Local static machine IP address • Subnet mask • Default gateway
TCP/IP Configuration (3) • Local machine IP address • DHCP protocol can automatically assign IP addresses from a Windows 2000 server machine running DHCP server • Alternatively, a static IP address can be keyed in manually • Subnet mask: • normally 255.255.255.0 for small networks • 255.255.x.0 for larger networks • x -> 0 as the network gets larger • Default gateway is the IP address of the LAN-Internet interface computer…
Windows TCP/IP utilities • Located in the system32 directory • Not available from the GUI • Only accessible via the NT prompt (Ping (packet internet groper): • FTP • Telnet • Finger (retrieval of system information from a computer running TCP/IP & finger • ARP (displays local IP addresses according to equivalent MAC or “physical” addresses) • ipconfig (displays local IP configuration) • tracert (checks route to a remote IP address)
Some Other Windows Network Services • Terminal Services • RIS (remote installation…) • DNS (Domain name/IP address look up) • Virtualisation (Hyper-V) • RAS (remote access) & Secure Remote Login • Internet Information Server (IIS)
Installation of Client-Server Services • Don’t need a domain controller • Many run quite happily on a Server • Investigation after the break…
“Internet of Things” • http://www.bcs.org/upload/pdf/internet-things-190213.pdf • http://www.youtube.com/watch?v=fj_xwgLW_4I