1. Name Resolution

2. How Names Are Mapped to IP Addresses Name Resolution Service 192.168.1.200 Myself.com Where is the myself.com? Myself.com 1 1 2 2 3 3

3. 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 www.company1.com server1.training.company1.com FQDN DNS Suffix Host Name DNS Suffix Host Name Server1 = 192.168.0.67 www = 192.168.0.66 com “.” Root company1 training

4. 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? Salescomputer2 1 1 2 2 3 3 192.168.1.35 Salescomputer2 Client Resolver Cache/Hosts File DNS NetBIOS Name Cache WINS Broadcast Lmhost File

5. 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

6. 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) 1993-1999 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: # # 102.54.94.97 rhino.acme.com # source server # 38.25.63.10 x.acme.com # x client host 127.0.0.1 localhost

7. 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 1 1 2 2 3 3