Transcript Slide 1

Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Network Naming
Chapter 10
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Objectives
• Describe the function and capabilities of DNS
• Configure and troubleshoot WINS
• Use common TCP/IP utilities to diagnose
problems with DNS and WINS
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Overview
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Introduction to naming
• Computers use IP addresses to communicate
• People remember names better than
numbers
• Name resolution created to convert names to
IP addresses (and vice versa)
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
•
•
•
•
Name resolution has evolved over the years
Main protocol is Domain Name System (DNS)
Operating systems support old and new
Windows, Linux, and Macintosh OS X still
support Windows Internet Name Server
(WINS)
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.1 Turning names into numbers
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Three parts to Chapter 10
• DNS
• WINS
• Diagnosing TCP/IP networks
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
DNS
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
DNS
• Early Internet use of HOSTS file
– One file copied to all hosts on the Internet
– Contained a list of IP addresses for every
computer, matched to system names
– Preceded rules for composing Internet
names
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• HOSTS file
– Preceded DNS
– Anyone could name computer anything
– Duplicate names not allowed
– Sample old HOSTS file:
• 192.168.2.1
• 201.32.16.4
• 123.21.44.16
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fred
SCHOOL2
SERVER
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• HOSTS file (cont.)
– HOSTS file updated on every system every
morning at 2 a.m.
– Impractical after Internet grew to 5000
– New name system, but HOSTS file still
exists
– # symbol indicates a line is a comment
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• HOSTS file (cont.)
– Every OS first looks in HOSTS file
– Follow-up to Try This!
• Every TCP/IP app looks at HOSTS file
• If you altered the HOSTS file per the Try This!,
enter this command:
ping timmy
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• HOSTS file (cont.)
– Some people place shortcut names in a
HOSTS file to avoid typing a long name
into browser
– DNS is more powerful and used much
more
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• How DNS works
– No single computer can handle all Internet
name resolution
– Delegation used
• Top-dog DNS system delegates parts of the job
• Subsidiary DNS systems delegate parts of their
work
• All DNS servers run a special DNS server program
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• How DNS works (cont.)
– Naming system facilitates delegation
– Top-dog DNS a bunch of powerful systems
• Dispersed around the world
• Known collectively as the DNS root servers (or
DNS root)
– The Internet name for DNS root is “.”
– Below root are the top-level domain servers
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Name spaces
– HOSTS file uses a flat name space
– DNS uses a hierarchical name space
• A hierarchy of DNS domains and computer names
• Hierarchical DNS name space is the DNS Tree
• Root is the holding area to which all domains
connect
• Individual computers have host names
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Name spaces (cont.)
– Home-brewed DNS
• Must not connect to the Internet
• Set up a DNS server to be the root server
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.2 Our People name space
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.3 Two DATA.TXT files in different
directories on the same system
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Name spaces (cont.)
– DNS naming syntax
• Opposite of disk folder/directory syntax
• A complete DNS name is a fully qualified domain
name (FQDN)
• Host and all domains in order
• Root is far right
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.4 Private DNS network
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.5 Two DNS domains
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.6 Subdomains added
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Key players in DNS
– DNS Name Server: running DNS software
– DNS Zone: A container for a single DNS
domain that gets populated with records
– DNS record: a line in the zone data that
maps an FQDN to an IP address
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Name servers
– One server is authoritative DNS server for
a domain
• a.k.a. Start of Authority (SOA)
• Other name servers (NS) are subordinate
• All DNS servers know the address of SOA and all
NS servers in the domain
• SOA keeps others updated
– Name servers can host multiple DNS
Domains
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Name servers (cont.)
– Other systems send queries to DNS servers
– Request resolution of FQDNs to IP addresses
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.7 A single SOA can support one or
more domains.
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.8 DNS flexibility
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.9 New information passed out
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.10 Root server in action
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.11 DNS domain
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Name resolution
– DNS not required to access Internet
– DNS just makes it much easier
– IP addresses required for connections
– Most people would not use Internet without
DNS name resolution
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Name resolution (cont.)
– Type Web address into a browser
– It must resolve the name to IP address
– Three ways to resolve a name
• Broadcasting
• HOSTS file
• Querying a DNS server
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.12 Any TCP/IP-savvy program accepts
either an IP address or an FQDN.
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.13 Routers don’t forward broadcasts!
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.14 A host contacts its local DNS server.
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.15 DNS information in Windows
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.16 Entering DNS information in Ubuntu
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.17 ipconfig /all showing DNS information
in Windows
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.18 Checking the DNS cache
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.19 Talking to a root server
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.20 Talking to the .com server
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.21 Talking to microsoft.com DNS server
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• DNS servers (in action)
– Most OSes have built-in DNS server software
• Server versions of Windows
• Most versions of UNIX/Linux
– Third-party DNS servers
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• DNS Servers (in action) (cont.)
– Three special storage areas
• Cached lookups
• Forward lookup zones
• Reverse lookup zones
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.22 DNS server main screen
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.23 Inspecting the DNS cache
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• DNS servers (in action) (cont.)
– Cache-only DNS servers
• Do not store lookup zones
• Talk to other DNS servers to resolve for clients
• Are never the authoritative server for a domain
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.24 Authoritative vs. cache-only DNS server
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Totalhome domain example
– Does not comply with Internet rules
– None of the computers is visible on Internet
– Only usable on private network
– Forward lookup is named totalhome
– All the DNS servers listed under NS records
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Totalhome forward lookup zone
– Each system in the domain has an A record
– An alias for a system is a canonical name
(CNAME)
– SMTP servers use MX records (Mail eXchanger)
– AAAA records are for IPv6 addresses
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.25 Forward lookup zone totalhome
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.26 Less common DNS record types
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Forward lookup zones
– Two types of forward lookup zones:
Primary zone and Secondary zone
– Resolve FQDN to IP address with
Reverse lookup zone
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.27 Two DNS servers with updating
taking place
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.28 Reverse lookup zone
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Windows DNS server
– Performs most functions exactly like
UNIX/Linux DNS servers
– Adds a Windows-only Active Directoryintegrated zone
– Avoids problems of standard DNS servers
– All domain controllers are DNS servers
– All DNS servers are equal
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Enter Windows
– 1980s Microsoft NetBIOS/NetBEUI
– 1990s Microsoft created NetBIOS over
TCP/IP – added NetBIOS naming to DNS
– Old sharing protocol Server Message Block
(SMB)
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.29 NetBIOS broadcast
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Enter Windows—NetBIOS over TCP/IP
– New sharing protocol Common Internet File
System (CIFS)
– SMB/CIFS adopted by UNIX/Linux and Mac
OS X
– CIFS and DNS work together
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.30 Samba on Ubuntu (it’s so common that the OS
doesn’t even use the term in the dialog box)
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Living with the legacy of CIFS
– Networks using CIFS use two name systems
– CIFS broadcast to find local server
– DNS query to find TCP/IP host
– CIFS and DNS work together
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Living with the legacy of CIFS (cont.)
– CIFS organizes computers into workgroups
– Computer joins a workgroup
– Flat name space
– See workgroups in Network/My Network
Places
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.31 Joining a workgroup
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.32 Two workgroups in Network folder
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Living with the legacy of CIFS (cont.)
– Computers controlled by Windows domain
controller server are grouped in a Windows
domain
– Windows computers join a domain
– Computers (and users) authenticate to the
domain
– Windows domains now use DNS naming
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.33 Logging in to the domain
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Living with the legacy of CIFS (cont.)
– An Active Directory domain is an
organization of computers that shares one
or more Windows domains
– All Active Directory Windows domain
controllers are DNS servers
– All domain controllers are equal partners
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.34 If one domain controller goes down,
another automatically takes over.
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Active Directory-integrated zones
– DNS info is stored in the AD database,
instead of text files
– AD is stored across several domain
controllers, so there’s no longer only one
copy
– Domain controllers automatically replicate
DNS zone information along with other AD
updates
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Dynamic DNS (DDNS)
– DNS previously required manual updates to
zone files
– This became very problematic as the
Internet and organization’s computers grew
in numbers
– Dynamic DNS (DDNS) enables a DNS server
to talk to a DHCP server and get IP
addressing info on its clients
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Dynamic DNS (cont.)
– Most modern DNS software can use DDNS
– Windows clients can also update DNS server
files automatically
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Dynamic DNS on the Web
– High-speed connections now enable home
computers to run as web and file servers,
and enable remote connections to it
– Problem existed with home or office
router-assigned DNS names
– Dynamic DNS maps home or office router
to a domain name
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Dynamic DNS on the Web (cont.)
– If router’s external IP address changes, it
notifies the dynamic DNS service and makes
the change
– Allows home or office network to be
contacted via domain name regardless of IP
address changes
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Troubleshooting DNS
– Client is source of most DNS problems
– DNS servers rarely go down
– If a DNS server is down, clients use
secondary DNS server
– Symptom: “server not found” error
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.35 DNS error
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Troubleshooting DNS (cont.)
– Eliminate any local DNS caches
• Do not use Web browser for troubleshooting
• On Windows, run ipconfig /flushdns
• Ping the name of a well-known Web site
– Does it return an IP address?
– If not, ping an IP address
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.36 Using ping to check DNS
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Troubleshooting DNS (cont.)
– If the previous steps indicate a problem with
the DNS server, run nslookup utility
• Queries functions of DNS servers
• Depends on proper permission level
• Use to change how your system uses DNS
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Troubleshooting DNS (cont.)
– Run nslookup without parameters to get
• IP address and name of default DNS server
• Error indicates primary DNS server is down or
client has wrong IP for DNS server
• nslookup has own prompt
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Troubleshooting DNS (cont.)
– UNIX/Linux tool: domain information groper
(DIG)
• Similar to nslookup
• Non-interactive
• Ask it a question; it answers
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
WINS
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
WINS
• Legacy NetBIOS
– Current versions of Windows use DNS
and/or CIFS
– NetBIOS names supported for backwards
compatibility
– NetBIOS system broadcasts its name
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Prior to CIFS
– LMHOSTS file
• Works for NetBIOS like HOSTS does for DNS
• Microsoft OSes still support
• Every Windows systems has an LMHOSTS file
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Windows Internet Naming Service (WINS)
– WINS server for legacy Windows
– No broadcasting: NetBIOS hosts register
with WINS
– Allows NetBIOS to function in a routed
network
– WINS proxy agent for legacy Windows
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.37 WINS server
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.38 Proxy agent
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Configuring WINS clients
– Enter IP address of WINS server
– WINS information can be added to DHCP
– WINS clients register NetBIOS names with
WINS server
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Troubleshooting WINS
– Most “WINS” problems are NetBIOS
problems
• Two systems sharing same name
• Change name of one system
– NBTSTAT
• Check name cache with nbtstat –c
• Determine if WINS server has given inaccurate info
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Diagnosing TCP/IP
networks
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Improper configuration causes most
problems
• Ping anyone you want to connect to
• Regardless of what the user cannot
connect to, you perform the same steps
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Use common sense
– If one system behaves differently than others,
the problem is with the client
– Before starting steps (below) check the network
connections and protocols
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Steps for troubleshooting TCP/IP
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Diagnose the NIC
Diagnose locally
Check IP address and subnet mask
Run netstat with no options
Run netstat –s
Diagnose to the gateway
Diagnose to the Internet
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.39 The net view command in action
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.40 The netstat command in action
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 10.41 Using tracert
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.