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Name Resolution. NetBIOS name resolution. NetBIOS name = computer name. Microsoft commands use NetBIOS names. Example: Net View \ computer_name NetBIOS names must be resolved to their TCP/IP addresses before a connection can be established. NBTStat utility.
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Name Resolution Prepared by: Information Technology Department
NetBIOS name resolution • NetBIOS name = computer name. • Microsoft commands use NetBIOS names. • Example: Net View \\ computer_name • NetBIOS names must be resolved to their TCP/IP addresses before a connection can be established. Prepared by: Information Technology Department
NBTStat utility nbtstat -n Lists all NetBIOS names registered in cache. nbtstat -R Clears name cache and reloads any names pre-loaded in LMHOSTS file. Prepared by: Information Technology Department
Computer 1 Computer 2 B-node (Broadcast node) NetBIOS names are resolved through broadcasts. Who is Computer 2? Prepared by: Information Technology Department
100.100.1.2 is Computer 2. Computer 1 Computer 2 B-node (Broadcast node) (cont.) NetBIOS names are resolved through broadcasts. Prepared by: Information Technology Department
P-node (Peer-to-peer node) NetBIOS name is resolved through directed datagrams to NetBIOS Name Server. To: NBNS Who is Computer 2? Computer 1 NBNS Computer 2 Prepared by: Information Technology Department
P-node (Peer-to-peer node) (cont.) NetBIOS name is resolved through directed datagrams to NetBIOS Name Server. To: NBNS Who is Computer 2? To: Computer 1 100.100.1.2 is Computer 2 Computer 1 NBNS Computer 2 Prepared by: Information Technology Department
To: NBNS Who is Computer 2? To: Computer 1 100.100.1.2 is Computer 2 Computer 1 NBNS Sends packet to Computer 2 Computer 2 P-node (Peer-to-peer node) (cont.) NetBIOS name is resolved through directed datagrams to NetBIOS Name Server. Prepared by: Information Technology Department
To: NBNS Who is Computer 2? Who is Computer 2? M-node vs. H-node M-node H-node Who is Computer 2? 1. 1. If no response If no response 2. 2. To: NBNS Who is Computer 2? Prepared by: Information Technology Department
NetBIOS name resolution and LMHOSTS LMHOSTS file - Maps IP addresses to NetBIOS names. Maintained in the winnt-root\system32\drivers\etc directory. #PRE - Pre-loads mapping into the NetBIOS name cache. #DOM: Domain_name - Indicates that the machine listed is a domain controller for that domain. Example: 100.100.1.2 Server1 #PRE #DOM: Domain2 Prepared by: Information Technology Department
Troubleshooting LMHOSTS files • Computer name misspelled. • Incorrect IP address. • LMHOSTS filename is incorrect (for example, LMHOSTS.TXT). • #PRE and #DOM tags missing or in lower case. • Registry on remote machine with LMHOSTS file not configured correctly. • Incorrect UNC path in #INCLUDE statements. • Duplicate entries for the same computer or IP address in LMHOSTS file. Prepared by: Information Technology Department
Microsoft host name resolution • Local host • HOSTS file • Domain Name System (DNS) • NetBIOS name cache • WINS server • Broadcasts • LMHOSTS file Prepared by: Information Technology Department
HOSTS file guidelines • Must be in \winnt_root\system32\drivers\etc path • Each entry 255 characters • Multiple names can be configured per IP address • Not case-sensitive • No special tags (#PRE, #DOM, #INCLUDE) supported • Include entry for localhost • File parsed from top to bottom • Precede any comments with a semicolon Prepared by: Information Technology Department
Troubleshooting HOSTS files • Misspelled computer or host names • Incorrect IP addresses • HOSTS filename misspelled or not in the correct format • Multiple entries for the same name or address in HOSTS file Prepared by: Information Technology Department
<Root> ntserver.zdeducation.com ntworkstation.zdeducation.com The DNS hierarchy .com .gov .edu microsoft.com whitehouse.gov berkeley.edu zdeducation.com dev.microsoft.com research.berkeley.edu labcomputer.research.berkeley.edu Prepared by: Information Technology Department
What is the address for server.company.com? Server.company.com is 137.105.21.5. The DNS Server service DNS client Windows NT server running DNS Server Prepared by: Information Technology Department