1. Name Resolution
Presented By
Tom Battaglia
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2. 4 Section presentation Section 1 - Resolution Methods Defined
Section 2 - Microsoft Name Resolution
Section 3 - The OSI Model
Section 4 - Troubleshooting
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3. Section 1 of 4 Resolution Methods Defined
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4. Resolution Methods What is Name resolution
Computers communicate using IP’s
People communicate using computer names
Name resolution is a result of a client query to get an IP address for a computer name
“Name Server” - The server that can hand out an IP after a query for one is made
NOTE: If a client uses an IP to communicate the Name Server is not necessary
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5. Resolution Methods Types of Resolution Methods
Broadcast for NetBIOS Name
WINS - Windows Internet Name Server
DNS - Domain Name Server
DDNS - Dynamic Domain Name Server
Node Type Resolution of Microsoft clients
B-node / P-node / M-node / H-node
LMHOST / HOST
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6. Broadcast for NetBIOS "Short" Name
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7. Resolution Methods Defined
Broadcast - Characteristics
Routers do not forward Broadcast requests off of the subnet
Only NetBIOS "Short"names can be resolved on the local subnet
Every Client on the subnet processes Broadcast packets
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8. Windows Internet Name Service (WINS)
Note: Microsoft Windows Clients Only
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9. Resolution Methods Defined WINS
WINS - Server Characteristics
Resolves NetBIOS "Short" Names only
i.e. Batman01
Client updates dynamic database on WINS server during startup or Nbtstat -RR
Admin can add static entries to WINS
ONLY Services are registered in WINS
WINS Servers exchange entries by being "Push/Pull" partners
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10. Resolution Methods Defined WINS
WINS - Client Characteristics
* Client DOES NOT use secondary unless primary WINS server is down
To resolve a name to an IP the client must be
using a WINS server that the destination server registered with OR
The clients WINS server is a "Push/Pull" partner of the destinations WINS server
* NT4 Only. W2K will use Secondary after a delay.
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11. Resolution Methods Defined WINS
WINS – Server Locations
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12. Resolution Methods Defined WINS
WINS – MMC Example
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13. Resolution Methods Defined WINS
WINS – Unique Type Examples
WINS Entry Type Service Registered
[00h] Computer Name Workstation Service
[03h] Computer Name Messenger Service for Computer
[20h] Computer Name File Server Service
[BEh] Computer Name Network Monitoring Agent Service
[03h] User Name Messenger Service for the logged on user
[1Bh] Domain Name Domain Master Browser Service – PDC
[1Dh] Domain Name Subnet Master Browser Service
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14. Resolution Methods Defined WINS
WINS – Group Type Examples
WINS Entry Type Service Registered
[00h] Domain Name Workstation Service Receives Browser Broadcasts
[1Ch] Domain Name Domain Controllers 1 PDC
24 BDCs
[1Eh] Domain Name Used by Browsers for Elections
[01h] --_MSBROWSE_ Registered by Subnet Master Browser
Returned to clients after Query
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15. Domain Name Service (DNS)
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16. Resolution Methods Defined DNS
DNS - Server Characteristics
Resolves Fully Qualified Domain Names "FQDN"
i.e. Batman01.us.dell.com.
Integrated Microsoft and UNIX Servers
All Registrations are Statically Entered
Provides Forward Lookup - Name to IP
Provides Reverse Lookup - IP to Name
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17. Resolution Methods Defined DNS
DNS - Client Characteristics
The Client uses Domain Suffixes to Lookup Names
i.e. "us.dell.com"
i.e. "dell.com"
Client WILL use Secondary if Name can not be Found on Primary DNS Server
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18. Resolution Methods Defined DNS
DNS – Domain Suffixes
NT4
Client / Server
Setup
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19. Resolution Methods Defined DNS
DNS – Forward Lookup MMC Example
IP Address
Host Names
IP Alias
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20. Resolution Methods Defined DNS
DNS – Forward Lookup Unix Example
IP Address
Host Names
IP Alias
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21. Resolution Methods Defined DNS
DNS – Reverse lookup MMC Example
Host Names
IP - First Octet
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22. Resolution Methods Defined DNS
DNS – Reverse lookup Unix Example
Filename
Host Names
IP - First Octet
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23. Dynamic Domain Name Service (DDNS)
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24. Resolution Methods Defined DDNS
DDNS - Server Characteristics
Resolves Fully Qualified Domain Names "FQDN"
i.e. Batman01.aus.amer.dell.com.
ONLY Microsoft W2K servers
Some Registrations are Statically Entered
Provides Forward Lookup - Name to IP
Provides Reverse Lookup - IP to Name
Proxy Lookup to the WINS Server
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25. Resolution Methods Defined DDNS
DDNS - Client Characteristics
The Client uses Domain Suffixes to Lookup Names
i.e. "aus.amer.dell.com"
i.e. "amer.dell.com"
Client WILL use Secondary if Name can not be Found on Primary DNS Server
Registrations are Dynamically Entered when the W2K client uses a DDNS server
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26. Resolution Methods Defined DDNS
DDNS – Domain Suffixes
W2K
Client / Server
Setup
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27. Resolution Methods Defined DDNS
DDNS – Forward Lookup MMC Example
IP Address
Host Names
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28. Resolution Methods Defined DDNS
DDNS – Reverse lookup MMC Example
Not currently implemented at Dell on the W2K DDNS platform
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29. Section 2 of 4 Microsoft Name Resolution
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30. Microsoft Name Resolution
Part 1 - Resolution Methods
B-node / P-node / M-node / H-node
LMHOST File
HOST File
Part 2 - Combined Resolution Methods
NetBIOS
DNS
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31. Part 1 Resolution Methods
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32. Microsoft Name Resolution
B-Node - Characteristics
Uses Broadcast NetBIOS Name Queries for Name Registration and Resolution
B-Node Limitations:
(1) Broadcasts Disturb every node on the Network
(2) Routers Typically do not Forward Broadcasts, so only NetBIOS Names on the Local Network can be Resolved
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33. Microsoft Name Resolution
P-Node - Characteristics
Uses NetBIOS Name Server (NBNS)
- Typically a WINS Server
P-Node Limitations:
(1) If the Server is not Registered with WINS the Client can not Resolve it
(2) If the NBNS is "Down" the Client May not Resolve or will use the Secondary with Degraded Results
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34. Microsoft Name Resolution
M-Node - Characteristics
Uses B-Node First
Uses P-Node if B-Node does not Resolve
M-Node Limitations:
(1) Broadcasts Disturb Every Node on the Network
(2) If the NBNS is "Down" the Client May not Resolve or will use the Secondary with Degraded Results
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35. Microsoft Name Resolution
H-Node - Characteristics
Uses P-Node First
Uses B-Node if B-Node does not Resolve
H-Node Advantages:
(1) It Does Not Use Broadcasts First
(2) It Will Resolve Faster Using WINS and cut down on Network Traffic
NOTE: This is the method Microsoft uses for all their Windows platforms
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36. Microsoft Name Resolution
LMHOST File - Characteristics
Used to resolve NetBIOS "Short" Names
Can have Entries Cached from file
Located in [%systemroot%\system32\drivers\etc]
LMHOST File Limitations:
(1) Can hold only 128 entries
(2) If a Name Changes all LMHOST Files Need to be Updated
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37. Microsoft Name Resolution
LMHOST File Example
LMHOST File - No Extension
LMHOST Sample File
Examples
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38. Microsoft Name Resolution
HOST File - Characteristics
Used to resolve FQDN Names
Can have Entries Cached from file
Located in [%systemroot%\system32\drivers\etc]
HOST File Limitations:
(1) If a Name Changes all HOST Files Need to be Updated
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39. Microsoft Name Resolution
HOST File Example
HOST File - No Extension
Examples
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40. Part 2 Combined Resolution Methods
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41. Microsoft Name Resolution
All Microsoft Platforms - NetBIOS
Uses B-Node if no WINS Server Specified
Uses H-Node Resolution if a WINS Server is Specified
If System Fails to Register with WINS it will Result in B-Node until it can Contact the WINS Server
Some Commands - Net View and Nbtstat
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42. Microsoft Name Resolution
M-Node
LMHOST
Cache
Broadcast
File
P-Node
LMHOST
Cache
WINS
File
M-Node
LMHOST
Cache
Broadcast
WINS
File
If Configured for "DNS for WINS Resolution (NT4)"
HOST
DNS Server
H-Node
LMHOST
Cache
WINS
Broadcast
File
If Configured for "DNS for WINS Resolution (NT4)"
HOST
DNS Server
NetBIOS Resolution
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43. Microsoft Name Resolution
An example of name resolution would be like calling information to get the # - (IP Address)
Try to remember the #
Call information to get a # for a name
The operator can put your call through
If the # is unlisted you might need to go in your front yard and call their name
Check the Counter for Pieces of Paper
You might check your personal phone list
Look it up in the phone book (FQDN)
Give up and go shopping
H-Node
Cache
WINS
Broadcast
LMHOST File
HOST File
DNS Server
Time Out
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44. Microsoft Name Resolution
All Microsoft Platforms - DNS / DDNS
Client will look on Server and Query Using the Domain Suffixes
Some Commands - Ping, Ftp, and Telnet
Suffix Search Order
DNS Server
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45. Microsoft Name Resolution
Microsoft Reference Articles
Q Differences Between the HOSTS and LMHOSTS Files in Windows NT
Q NetBIOS over TCP-IP Name Resolution and WINS
Q TCP-IP & NBT Configuration Parameters for Windows NT and Windows 2000
Q Description of TCP-IP Node-Type Settings in Windows 95-98
Q NetBIOS Name Resolution Using DNS and the HOSTS File
Q Windows TCP-IP Registry Entries
Q Default Node Type for Microsoft Clients
Q Automatically Changing the Node Type of a Windows NT Workstation
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46. Section 3 of 4 The OSI Model
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47. Open Systems Interconnection (OSI) Model
OSI Characteristics
Describes how information from a software application in one computer moves through a network medium to a software application in another computer
Developed by the International Organization for Standardization (ISO) in 1984
Each layer being implemented independently enables the solutions offered by one layer to be updated without adversely affecting the other layers
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48. Open Systems Interconnection (OSI) Model
OSI Characteristics
Data Encapsulation and Decapsulation occurs as each layer passes data up and down the stack
Layered approach for ease of Learning, Modular Engineering, Interoperability and Eases Standards Development
Ethernet = Frames
TCP/IP = Packets
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49. Open Systems Interconnection (OSI) Model
Layer 7 — Application layer
Layer 6 — Presentation layer
Layer 5 — Session layer
Layer 4 — Transport layer
Layer 3 — Network layer
Layer 2 — Data Link layer
Layer 1 — Physical layer
Implemented with software
Implemented with Software
& Hardware
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50. Open Systems Interconnection (OSI) Model
"FYI" OSI Compared to TCP/IP Stack
OSI 7 Layers TCP/IP 4 Layers
Application
Presentation
Session
Transport
Network
Data Link
Physical
Application
Transport
Internet
Interface
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51. Open Systems Interconnection (OSI) Model
Each layer communicates with three other OSI layers:
The layer directly above it,
The layer directly below it
Its peer layer in other networked device
Application
Presentation
Session
Transport
Network
Data Link
Physical
Application
Presentation
Session
Transport
Network
Data Link
Physical
Upper Layer
"Service User"
Peer-to-Peer
Communication
Protocol Data Units
(PDU)
Lower Layer
"Service Provider"
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52. Open Systems Interconnection (OSI) Model
Application
Layer 6
Layer 5
Layer 4
Layer 3
Layer 2
Layer 1
Interface to Application
Interface to User
UDP Application examples
DHCP
BOOTP
TFTP
TCP Application examples
HTTP
FTP
TELNET
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53. Open Systems Interconnection (OSI) Model
Layer 7
Presentation
Layer 5
Layer 4
Layer 3
Layer 2
Layer 1
"Translator"
Encryption
Decryption
Compression
Decompression
Architecture Independent data transfer format. i.e.
MPEG
Gif
Jpeg
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54. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Session
Layer 4
Layer 3
Layer 2
Layer 1
"Coordinator"
Manage User Sessions
Establish Connection
Manage Connection
Terminate Connection
Report upper layer errors
Protocols
AppleTalk
Session Control Protocol
DECnet Phase 5
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55. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Layer 5
Transport
Layer 3
Layer 2
Layer 1
"Segmenter"
Reliable Packet Delivery
Flow Control
Multiplexing
Error Checking
Protocols Used
TCP
UDP
SPX
NetBEUI
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56. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Layer 5
Layer 4
Network
Layer 2
Layer 1
"Packet" (Data gram)
Logical Addressing
Path Determination (Routing)
Connectionless
Best-Effort-Delivery
Address Res. Protocol -ARP
IP to MAC
Routed Protocols
IP / IPX / ICMP
Routing Protocols
OSPF / RIP / BGP
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57. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Layer 5
Layer 4
Layer 3
Data Link
Layer 1
"Frame"
Switches Operate Here
All devices talk MAC
Header Contains MAC Address
Error Notification
Network Topology Defined
Flow Control
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58. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Layer 5
Layer 4
Layer 3
Data Link
Layer 1
Data Link Layer Sub layers
Logical Link Control - LLC
802.2
Connectionless & Connection Oriented
Media Access Control - MAC
Manage protocol access to the physical layer
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59. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Layer 5
Layer 4
Layer 3
Data Link
Layer 1
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60. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Layer 5
Layer 4
Layer 3
Layer 2
Physical
"Link"
Changes data to electrical impulses
Transmits "Bits" onto the Wire
Removes "Bits" off the Wire
Physical error checking
Does not add or take away from the Frame
Concerned with Physical protocol and not Data Protocol
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61. Open Systems Interconnection (OSI) Model
Layer 7
Layer 6
Layer 5
Layer 4
Layer 3
Layer 2
Physical
Maintains the Physical Link
Defines the physical medium
Voltage levels & timings
Data Rates
Transmission Distance
Connectors
Cables
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62. Section 4 of 4 Troubleshooting
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63. Troubleshooting Part 1 - Basic Network Troubleshooting
Part 2 - NetBIOS Troubleshooting
Broadcast / WINS / LMHOST File
Part 3 - FQDN Troubleshooting
DNS / DDNS / Host File
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64. Part 1 Basic Network Troubleshooting
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65. Troubleshooting Basics
Client Considerations
ONLY GATHER FACTS………..
Don't trust the end user to evaluate.
Is it "Slow" or "Not Working"?
They Say "It's Dead" ……… It's Really been "Slow" Once Today
Can Other Clients get to the Server?
They Say "No One" ………It's Really "Everyone Can"
When Did it Work Last?
They Say "Last Week" …… It's Really "Never"
What Changed?
They Say "Nothing" ……… It's Really their Kids Game They Installed
Is the Client Properly Configured?
They Say "Yes" ……….. They Don't know what a Computer is
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66. Troubleshooting Basics
Server Considerations
ONLY GATHER FACTS………..
Is it Static or DHCP?
Can the Server Resolve Names?
When Did it Work Last?
What Changed?
Is the Server Properly Configured?
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67. Troubleshooting Basics
Parts to Troubleshoot
Separate the network from the Servers
Cables, Switches and Routers are the Net
Computers are the Clients and Servers
If the Network has a Problem Usually Several People are Affected
Check the Physical Layer
Is it the Correct Cable
Is there a Link Light
Does another Computer work in the port
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68. Troubleshooting Basics
Parts to Troubleshoot
Check the Computer Configuration
Configuration Docs
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69. Troubleshooting Basics
Parts to Troubleshoot
Check the Computer Configuration
Set CLASSID for W2K DHCP Clients
Capital W2K
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70. Troubleshooting Basics
Parts to Troubleshoot
Check the Computer Configuration
Domain Suffixes
Subnet Mask
WINS & DNS Servers
Class ID
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71. Troubleshooting Basics
Remove Name Resolution From The Test
PING Remote by IP
Ping Gateway by IP
Ping Loopback ( )
Map Drive by IP i.e. net use * \\ \c$
Tracert to IP i.e. tracert
"Net View" to IP i.e. net view \\
NOTE: Resolve ALL IP Issues Prior to Troubleshooting Name Resolution Issues
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72. Troubleshooting Basics
PING IP Example
Try to Resolve Name
Name Resolved
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73. Troubleshooting Basics
Tracert Example
Found
Not Found
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74. Troubleshooting Basics
Netstat Syntax
"/?" Display Help
Switches
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75. Troubleshooting Basics
Netstat -a Example
Port State
Protocol
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76. Troubleshooting Basics
Netstat -n Example
Port State
Protocol
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77. Troubleshooting Basics
Netstat -r Example
Default Gateway
Remote
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78. Troubleshooting Basics
Netstat -s Example
Is Data Moving ?
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79. Part 2 NetBIOS Troubleshooting
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80. Troubleshooting NBNS (WINS)
Client Considerations
Can Not Login to the Domain
"No Domain Controller Found"
Can Not Map a Drive by Name
"Host Name Not Found"
Can Not "Net View" a computer
What WINS Server are they using
Can Other Computers Map Drives by Name
Does Not Need to Register with WINS to Resolve
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81. Troubleshooting NBNS (WINS)
Server Considerations
Are all the Services Registered in WINS?
The Name Resolution is up to the Client if all the Server Services are Registered in WINS
If the Server is down several people are having the SAME problem(s)
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82. Troubleshooting NBNS (WINS)
Add Name Resolution To The Test
"Nbtstat" to "Short Name"
i.e. nbtstat -a \\ausgnsnpt01
"Net View" to "Short Name"
i.e. net view \\ausgnsnpt01
Map Drive by "Short Name"
i.e. net use * \\ausgnsnpt01\c$
PING Remote by "Short Name"
i.e. Ping ausgnsnpt01
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83. Troubleshooting NBNS (WINS)
Nbtstat Syntax
"/?" Display Help
Switches
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84. Troubleshooting NBNS (WINS)
Nbtstat -a Example
"-a" Remote
Services & MAC
"-n" Local
Services NO MAC
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85. Troubleshooting NBNS (WINS)
Nbtstat -c Example
"-c" Cache
"-r" Resolved
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86. Troubleshooting NBNS (WINS)
Nbtstat -s and -RR Example
"-s or -S" Sessions
"-RR" ReRegister with WINS
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87. Troubleshooting NBNS (WINS)
Net View Syntax and Example
Show Browse List
"Short Name"
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88. Troubleshooting NBNS (WINS)
Net Use Syntax and Example
Map next Drive Letter
Ask for Password
Delete Map
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89. Troubleshooting NBNS (WINS)
PING Example
Note: PING is a DNS Command for FQDN but can be used to troubleshoot Net BIOS
FQDN Name Resolved by DNS
"Short Name" Resolved by Broadcast or WINS
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90. Troubleshooting NBNS (WINS)
LMHOST File
Clear the LMHOST file if not needed or you are troubleshooting
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91. Part 3 FQDN Troubleshooting
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92. Troubleshooting DNS/DDNS (FQDN)
Client Considerations
Does the App use FQDNs?
Is the Domain Suffix Correct?
Check for the correct Name Server
Is the IP Address in DNS or DDNS
us.dell.com - Legacy
aus.amer.dell.com - W2K
Can Not Map a Drive by FQDN
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93. Troubleshooting DNS/DDNS (FQDN)
Server Considerations
Is the Name in DNS or DDNS?
The Name Resolution is up to the Client if the server is in DNS or DDNS it has met the minimum requirements
If the Server is down several people are having the SAME problem(s)
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94. Troubleshooting DNS/DDNS (FQDN)
NSLookup Syntax
Show Commands
Commands
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95. Troubleshooting DNS/DDNS (FQDN)
NSLookup Example
Authoritative
amer.dell.com
DDNS Server
Query Returned
Non-Authoritative
amer.dell.com
DDNS Server
Query Returned
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96. Troubleshooting DNS/DDNS (FQDN)
NSLookup Example
Non-Authoritative
us.dell.com
DDNS Server
Query Returned
Query Returned
No DNS Entry
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97. Troubleshooting DNS/DDNS (FQDN)
PING Syntax
Show Syntax
Switches
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98. Troubleshooting DNS/DDNS (FQDN)
PING Example
PING Loop Back Address
TCP/IP is Installed Properly
Loop Back Address
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99. Troubleshooting DNS/DDNS (FQDN)
PING Example
Domain Suffix Search Order
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100. Troubleshooting DNS/DDNS (FQDN)
PING Example
Domain Suffix Search Order
Ping Short Name
WINS Responded with "Short Name"
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101. Troubleshooting DNS/DDNS (FQDN)
PING Example
Domain Suffix Search Order
Ping Short Name
DDNS Responded with FQDN
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102. Troubleshooting DNS/DDNS (FQDN)
PING Example
PING Loop Back Name in Host File
TCP/IP is Installed Properly
Host File is Working
Loop Back Name "Localhost"
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103. Name Resolution
Presented By
Tom Battaglia
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