Module 4: Resolving Names

Overview Multimedia: Introduction to the Name Resolution Process Viewing Names on a Client Configuring Host Name Resolution Configuring NetBIOS Name Resolution

Multimedia: Introduction to the Name Resolution Process The objective of this presentation is to provide a high-level overview of the name resolution process in the network infrastructure After this presentation, you will be able to:  Explain what a host name is  Explain what a NetBIOS name is  Describe how the name resolution process works

Lesson: Viewing Names on a Client How Names Are Mapped to IP Addresses What Are Host Names? What Are NetBIOS Names? How to View Names On a Client

How Names Are Mapped to IP Addresses Name Resolution Service Computer44 Where is the Computer44 file? Computer

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.nwtraders.msft. server1.training.nwtraders.msft. FQDN DNS Suffix Host Name DNS Suffix Host Name Server1 = Server1 = msft “.” Root nwtraders training

What Are NetBIOS Names? Server2 NetBIOS Name16 th characterServicesIP address Server200Workstation Server220Server Server201Messenger A NetBIOS name is an identifier used by NetBIOS services running on a computer. It is made up of a 15-character name plus a 16th character (byte) denoting the service

How to View Names on a Client Your instructor will demonstrate how to: View host names and DNS suffixes by using the Ipconfig utility View host names by using System Properties View NetBIOS names by using the Nbtstat command View your computer’s NetBIOS name by using System Properties Rename a computer View host names and DNS suffixes by using the Ipconfig utility View host names by using System Properties View NetBIOS names by using the Nbtstat command View your computer’s NetBIOS name by using System Properties Rename a computer

Practice: Viewing Names on a Client In this practice, you will view names on a client

Lesson: Configuring Host Name Resolution The Host Name Resolution Process Client Resolver Cache How to View and Flush the Client Resolver Cache Hosts File How to Preload the Client Resolver Cache by Using a Hosts File

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 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

How to View and Flush the Client Resolver Cache Your instructor will demonstrate how to: Display a client resolver cache by using the Ipconfig command Flush a client resolver cache by using the Ipconfig command Display a client resolver cache by using the Ipconfig command Flush a client resolver cache by using the Ipconfig command

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

How to Preload a Client Resolver Cache by Using a Hosts File Your instructor will demonstrate how to preload the client resolver cache by using a Hosts file

Practice: Configuring Host Name Resolution In this practice, you will configure host name resolution

Lesson: Configuring NetBIOS Name Resolution NetBIOS Name Resolution Process NetBIOS Name Cache How to View and Release the NetBIOS Name Cache Broadcasts Lmhosts File How to Preload a NetBIOS Name Cache by Using an Lmhosts File

NetBIOS Name Resolution Process NetBIOS name resolution is the process of mapping a NetBIOS name to an IP address What is the IP address for Salescomputer2? What is the IP address for Salescomputer2? Salescomputer Salescomputer2 NetBIOS Name Cache WINS Broadcast Lmhosts File 2 2

Resolved host names from the WINS server Resolved host names from the WINS server Computer1 NetBIOS Name Cache Lmhosts File Resolved host names from broadcasts Resolved host names from broadcasts A NetBIOS name cache is a location in memory that stores NetBIOS names that have recently been resolved to IP addresses whether through a WINS server, broadcast, or Lmhosts file Broadcast

How to View and Release the NetBIOS Name Cache Your instructor will demonstrate how to: View the contents of the local computer’s NetBIOS name cache Release the NetBIOS name cache and reload the #PRE- tagged entries in the local Lmhosts file Display and view the NetBIOS name table of the local computer View the contents of the local computer’s NetBIOS name cache Release the NetBIOS name cache and reload the #PRE- tagged entries in the local Lmhosts file Display and view the NetBIOS name table of the local computer

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

Lmhosts File An Lmhosts file is a local text file that maps NetBIOS names to IP addresses for hosts that are not located on the local subnet Computer1 Lmhosts File # Copyright (c) Microsoft Corp. # # This is a sample LMHOSTS file used by the Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to computernames # (NetBIOS) names. Each entry should be kept on an individual line. # The IP address should be placed in the first column followed by the # corresponding computername. The address and the computername # should be separated by at least one space or tab. The "#" character # is generally used to denote the start of a comment (see the exceptions # below). # # The following example illustrates all of these extensions: # # rhino #PRE #DOM:networking #net group's DC # "appname \0x14" #special app server # popular #PRE #source server # localsrv #PRE #needed for the include # # #BEGIN_ALTERNATE # #INCLUDE \\localsrv\public\lmhosts # #INCLUDE \\rhino\public\lmhosts # #END_ALTERNATE

How to Preload a NetBIOS Name Cache by Using an Lmhosts File Your instructor will demonstrate how to preload a NetBIOS name cache by using an Lmhosts file

Practice: Configuring NetBIOS Name Resolution In this practice, you will configure NetBIOS name resolution

Lab A: Resolving Names In this lab, you will resolve names