Name Resolution

How Names Are Mapped to IP Addresses Name Resolution Service Myself.com Where is the myself.com? Myself.com

Examples: A host name is the DNS name, of a device on a network, that is used to locate computers on the network What Are Host Names? FQDN server1.training.company1.com FQDN DNS Suffix Host Name DNS Suffix Host Name Server1 = www = com “.” Root company1 training

The Host Name Resolution Process Host name resolution is the process of resolving a host name to an IP address What is the IP address for Salescomputer2? What is the IP address for Salescomputer2? Salescomputer Salescomputer2 Client Resolver Cache/Hosts File DNS NetBIOS Name Cache WINS Broadcast Lmhost File

Client Resolver Cache to View and Flush the Client Resolver Cache The client resolver cache is a location in memory that stores host names that have recently been resolved to IP addresses. It also stores host name- to-IP address mappings loaded from the Hosts file Computer1 Hosts File Resolved host names from the DNS server Resolved host names from the DNS server

Hosts File The Hosts file is a static file that is maintained on the local computer and that is used to load host name-to-IP address mappings into the client resolver cache Computer1 Hosts File # Copyright (c) Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to host names. Each # entry should be kept on an individual line. The IP address should # be placed in the first column followed by the corresponding host name. # The IP address and the host name should be separated by at least one # space. # # Additionally, comments (such as these) may be inserted on individual # lines or following the machine name denoted by a '#' symbol. # # For example: # # rhino.acme.com # source server # x.acme.com # x client host localhost

Broadcasts Broadcast Router NetBIOS Redirector NetBIOS Redirector The NetBIOS redirector sends out a local broadcast 1 1 If the resource is on the local network, the broadcast is answered and an IP address is returned 2 2 If the resource is on a remote network, then the broadcast will not pass through the router 3 3 Local broadcasts are network messages, sent from a single computer, that are distributed to all other devices on the same segment of the network as the sending computer Broadcast is answered Broadcast Fails