Module 8: Networking Services 3.5 Understand Networking Services 3.4 Understand Names Resolution

Agenda 1 Common Networking Services 2 Name Resolution Techniques

Common Networking Services

DHCP Dynamic Host Configuration Protocol (DHCP) is a client/server protocol that enables configured client computers to obtain IP addresses automatically The IP information obtained might include the following: IP addresses Subnet masks Gateway addresses DNS server addresses Other advanced options The DHCP Server service provides the following benefits: Reliable IP address configuration Reduced network administration

DHCP Server Before a DHCP server can start leasing IP addresses to client computers, the following steps must be performed: Install the DHCP service Configure an IP scope Activate the scope Authorize the server Configure advanced IP options (optional)

DORA DHCP sessions use a four-step process known as DORA. Discovery: The client sends a broadcast to the network to find a DHCP server Offer: The DHCP server sends a unicast “offering” of an IP address to the client Request: The client broadcasts to all servers that it has accepted the offer Acknowledge: The DHCP server sends a final unicast to the client that includes the IP information the client will use DHCP utilizes ports 67 and 68

APIPA Assigns unique IP addresses within the APIPA range when no DHCP server is available APIPA can get in the way of a client obtaining an IP address properly (e.g., when a client attempts to obtain an IP address from a DHCP server, but the DHCP server is too busy) Will prevent a computer from accessing the Internet Can communicate with other devices on a LAN

Remote Desktop Services (RDS) A type of thin-client terminal server computing RDS enables virtual desktop infrastructure (VDI), session-based desktops, and applications, allowing users to work anywhere Thin-client computers and PCs can connect to servers running Remote Desktop Services Bing up Server PosterPedia

Name Resolution Techniques

Domain Name System (DNS) DNS is a worldwide service that resolves host names to IP addresses DNS architecture is a hierarchical distributed database and an associated set of protocols that define: A mechanism for querying and updating the database A mechanism for replicating the information in the database among servers DNS is part of the application layer of the TCP/IP reference model DNS servers use inbound port 53 to accept name resolution requests

How does DNS work? Clients access libraries called resolvers to perform DNS queries There are two types of DNS queries: Recursive: Server responds with destination IP address or an error message Iterative: Server points client to a different DNS server

WINS Windows Internet Name Service (WINS) is a service that resolves NetBIOS names to IP addresses WINS is required for any environment in which users access resources that have NetBIOS names It is Microsoft’s version of the NetBIOS Name Service (NBNS) combined with a name server If you do not use WINS in such a network, you cannot connect to a remote network resource by using its NetBIOS name unless you use Lmhosts files, and you might be unable to establish file and print sharing connections

Summary 1 Common Networking Services 2 Name Resolution Techniques