Transcript Slide 1

Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Network Troubleshooting
Chapter 20
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Objectives
• Describe appropriate troubleshooting
tools and their functions
• Analyze and discuss the troubleshooting
process
• Tackle a variety of troubleshooting
scenarios
© 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
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Introduction to network
troubleshooting
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Three parts to Chapter 20
• Troubleshooting tools
• The troubleshooting process
• Troubleshooting scenarios
© 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 tools
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Hardware tools
–
–
–
–
–
–
–
–
–
Cable tester, TDR, and OTDR
Certifiers
Voltage event recorder/temperature monitor
Protocol analyzer
Cable stripper/snips
Multimeter
Tone probe and tone generator
Butt set
Punchdown tool
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Hardware tools (cont.)
– Cable testers, TDRs, and OTDRs
• Devices to test for broken cables
– Cable testers
» Continuity problems and wire map
– TDRs (time domain reflectometers)
» Locates copper cable breaks
– OTDRs
» Locates fiber-optic cable breaks
© 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 20.1 Typical cable tester
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 20.2 An EXFO AXS-100 OTDR (photo courtesy
of EXFO)
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Certifiers
– Only use for slowdowns, not disconnects
– Require a loopback on the far end
– Ensure a cable can handle its rated capacity
– Problems that reduce cable capacity
• Crosstalk
• Attenuation
• Interference
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Voltage event recorder/temperature
monitor
– Detect power and heat problems
– Cause intermittent problems
– Heat problems in server rooms
– Monitor power with voltage event recorder
– Monitor temperature with temperature
monitor
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Protocol analyzers
– Monitor protocols at different layers
• Application, Session, Transport, Network, Data
Link
– Both hardware and software tools
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• When to use a protocol analyzer
– You need to see data to analyze the problem
• A session fails to start
• A DNS server fails to respond
• Confusing information appears on the network
• You suspect a rogue DHCP server exists
• Excess traffic is slowing down the network
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Cable stripper or snip
– Enable you to make UTP cables
– Also need crimpers
– Often combined in one tool
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Figure 20.3 A cable stripping and crimping tool
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Multimeters
– Test AC and DC voltage
– Test resistance
– Test continuity
– A great fallback when you do not have
a cable tester
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Tone probes and tone generators
– Work together to identify opposite ends of
unlabeled cable runs
– Tone generator puts a signal (tone) on wire
– Tone probe on opposite end detects the
signal
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Butt sets
– Hand set
– Use to tap into a 66- or 110-block to
test a line
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Punchdown tools
– Put UTP wires into 66- and 110-blocks
– Repunch a connection to make sure
contacts are set
© 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 20.4 A punchdown tool in action
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Software tools
– Built-in commands and utilities:
o tracert/traceroute
o ipconfig/ifconfig
o
o
o
o
o
o
o
ping and arping
nslookup/dig
hostname
mtr
route
nbtstat
netstat
– Packet sniffer
– Port scanners
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• tracert/traceroute
– Traces all routers between two points
– Use to discover where a problem lies
– Problem is just beyond the last router
displayed before error
– Some routers block traceroute packets
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Tracing route to adsl-208-190-121-38.dsl.hstntx.swbell.net
[208.190.121.38] over a maximum of 30 hops:
1
1 ms
<1 ms
1 ms Router.totalhome
[192.168.4.1]
2
38 ms
41 ms
70 ms adsl-208-190-12138.dsl.hstntx.swbell.net [208.190.121.38]
Listing 20-1 Sample traceroute output
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• ipconfig/ifconfig
– Displays IP settings
– ipconfig without parameters
• Basic information only
– ipconfig /all gives configuration details
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Ethernet adapter Main:
Connection-specific DNS Suffix
IPv6 Address . . . . . . . . .
Temporary IPv6 Address . . . .
Link-local IPv6 Address. . . .
IPv4 Address . . . . . . . . .
Subnet Mask . . . . . . . . .
Default Gateway . . . . . . .
.
.
.
.
.
.
.
:
:
:
:
:
:
:
2001:470:bf88:1:fc2d:aeb2:99d2:e2b4
2001:470:bf88:1:5e4:c1ef:7b30:ddd6
fe80::fc2d:aeb2:99d2:e2b4%8
192.168.4.27
255.255.255.0
fe80::223:4ff:fe8c:b720%8
192.168.4.1
Tunnel adapter Local Area Connection* 6:
Media State . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Listing 20-2 Sample ipconfig output
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Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
eth0
Link encap:Ethernet HWaddr 00:02:b3:8a:7d:ae
inet addr:192.168.4.19 Bcast:192.168.4.255 Mask:255.255.255.0
inet6 addr: 2001:470:bf88:1:202:b3ff:fe8a:7dae/64 Scope:Global
inet6 addr: fe80::202:b3ff:fe8a:7dae/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2206320 errors:0 dropped:0 overruns:0 frame:0
TX packets:925034 errors:0 dropped:0 overruns:0 carriers:0
collisions:0 txqueuelen:1000
RX bytes:292522698 (292.5 MB) TX bytes:132985596 (132.9 MB)
lo
Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:15414 errors:0 dropped:0 overruns:0 frame:0
TX packets:15414 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1006671 (1.0 MB) TX bytes:1006671 (1.0 MB)
Listing 20-3 Sample ifconfig output
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• ping
– Queries by name or IP address
– Uses ICMP packets
– Works across routers
– Problem: devices can block ICMP
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Pinging 192.168.4.19 with 32 bytes
Reply from 192.168.4.19: bytes=32
Reply from 192.168.4.19: bytes=32
Reply from 192.168.4.19: bytes=32
Reply from 192.168.4.19: bytes=32
of data:
time<1ms
time<1ms
time<1ms
time<1ms
TTL=64
TTL=64
TTL=64
TTL=64
Ping statistics for 192.168.4.19:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
Listing 20-4 Sample ping output
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• arping
– Queries by IP address
– Uses ARP frames
– Problem: does not cross routers
– Only on UNIX and UNIX-like systems
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
ARPING 192.168.4.27 from 192.168.4.19 eth0
Unicast reply from 192.168.4.27 [00:1D:60:DD:92:C6]
Unicast reply from 192.168.4.27 [00:1D:60:DD:92:C6]
Unicast reply from 192.168.4.27 [00:1D:60:DD:92:C6]
Unicast reply from 192.168.4.27 [00:1D:60:DD:92:C6]
Listing 20-5 Sample arping output
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
0.875ms
0.897ms
0.924ms
0.977ms
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• nslookup/dig
– Both diagnose DNS problems
– nslookup (all operating systems)
• Poor tool – considered obsolete
• Without switches, provides name and
IP address of default DNS server
– dig – more powerful
• Every OS but 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)
dig mx totalsem.com
Listing 20-6 The dig command
; <<>> DIG 9.5.0-P2 <<>> mx totalsem.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6070
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
;; QUESTION SECTION:
;totalsem.com.
IN
MX
;; ANSWER SECTION:
totalsem.com.
86400
IN
MX
10
mx1c1.megamailservers.com.
totalsem.com.
86400
IN
MX
100
mx2c1.megamailservers.com.
totalsem.com.
86400
IN
MX
110
mx3c1.megamailservers.com.
Listing 20-7 Output for the dig command
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• hostname
– Simplest of all utilities
– Returns name of host from which it runs
– hostname sample output
c:\>
c:\>hostname
Mike-win7beta
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• My Traceroute (mtr)
– Dynamic (keeps running)
– Equivalent to traceroute
– Not available 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)
My traceroute [v0.73]
totaltest (0.0.0.0)
Keys: Help
Display mode
Restart statistics Order of fields quit
Packets
Pings
Host
Loss%
Snt Last
Avg Best Wrst StDev
1. Router.totalhome
0.0%
5
0.8
0.8
0.7
0.9
0.1
2. adsl-208-190-121-38.dsl.hstntx.s
0.0%
4 85.7 90.7 69.5 119.2 20.8
Listing 20-9 Sample mtr output
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• route
– Display and edit local routing table
– Type route print
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
===========================================================================
Interface List
8 ...00 1d 60 dd 92 c6 ...... Marvell 88E8056 PCI-E Ethernet Controller
1 ........................... Software Loopback Interface 1
===========================================================================
IPv4 Route Table
===========================================================================
Active Routes:
Network Destination
Netmask
Gateway
Interface
Metric
0.0.0.0
0.0.0.0
192.168.4.1
192.168.4.27
10
127.0.0.0
255.0.0.0
On-link
127.0.0.1
306
127.0.0.1 255.255.255.255
On-link
127.0.0.1
306
127.255.255.255 255.255.255.255
On-link
127.0.0.1
306
169.254.0.0
255.255.0.0
On-link
192.168.4.27
286
169.254.214.185 255.255.255.255
On-link 169.254.214.185
276
169.254.255.255 255.255.255.255
On-link
192.168.4.27
266
192.168.4.0
255.255.255.0
On-link
192.168.4.27
266
192.168.4.27 255.255.255.255
On-link
192.168.4.27
266
192.168.4.255 255.255.255.255
On-link
192.168.4.27
266
224.0.0.0
240.0.0.0
On-link
127.0.0.1
306
224.0.0.0
240.0.0.0
On-link 169.254.214.185
276
224.0.0.0
240.0.0.0
On-link
192.168.4.27
266
255.255.255.255 255.255.255.255
On-link
127.0.0.1
306
255.255.255.255 255.255.255.255
On-link 169.254.214.185
276
255.255.255.255 255.255.255.255
On-link
192.168.4.27
266
===========================================================================
Persistent Routes:
None
Listing 20-10 Sample route print output
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• nbtstat
– Windows (all versions) only
– Command-line equivalent of My Network
Places
– Must use a switch
– nbtstat –n shows local NetBIOS names
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Main:
Node IpAddress: [192.168.4.27] Scope Id: []
NetBIOS Local Name Table
Name
Type
Status
--------------------------------------------MIKESPC
<00> UNIQUE
Registered
TOTALHOME
<00> GROUP
Registered
MIKESPC
<20> UNIQUE
Registered
TOTALHOME
<1E> GROUP
Registered
Listing 20-11 Sample nbtstat output
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• netstat
– Shows current state of running IP processes
– Shows what sessions are active
– Provides statistics based on ports or
protocols
– Type netstat to show only current sessions
– Type netstat –r to show routing table (like
route print)
© 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 Connections
Proto
Local Address
TCP
127.0.0.1:27015
TCP
127.0.0.1:51090
TCP
127.0.0.1:52500
TCP
192.168.4.27:54731
TCP
192.168.4.27:55080
TCP
192.168.4.27:56126
TCP
192.168.4.27:62727
TCP
192.168.4.27:63325
TCP
192.168.4.27:63968
Foreign Address
MikesPC:51090
MikesPC:27015
MikesPC:52501
72-165-61-141:27039
63-246-140-18:http
acd4129913:https
TOTALTEST:ssh
65.54.165.136:https
209.8.115.129:http
State
ESTABLISHED
ESTABLISHED
ESTABLISHED
CLOSE_WAIT
CLOSE_WAIT
ESTABLISHED
ESTABLISHED
TIME_WAIT
ESTABLISHED
Listing 20-12 Sample netstat output
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Packet sniffer
– A.k.a. protocol analyzer or packet analyzer
– Intercepts and logs network packets
– Many choices
– Software example: Wireshark
– Dedicated hardware devices
© 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 20.5 Wireshark 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)
• Port scanners
– Probes remote system’s ports
– Logs state of scanned ports
– Good use: find unintentionally opened
ports in order to close
– Bad use: find open ports and use to break in
– nmap runs on UNIX and Windows
– Angry IP Scanner for 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 20.6 Angry IP Scanner
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• Throughput testers
– Enable you to measure the data flow in a
network
– Which tool to use depends on what part of
network you want to test
– Several speed-testing Web sites available for
checking an Internet connection’s
throughput
© 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 20.7 Speed test results from Speakeasy
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
The troubleshooting
process
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Memorize these problem analysis steps:
• Identify the problem
–
–
–
–
Gather information
Identify symptoms
Question users
Determine if anything has changed
• Establish a theory of probable cause
– Question the obvious
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Memorize these problem analysis steps
(cont.):
• Test the theory to determine cause
– Once theory is confirmed, determine next steps to
resolve problem
– If theory is not confirmed, re-establish new theory or
escalate
• Create an action plan and solution identifying
potential effects
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
Memorize these problem analysis steps
(cont.):
• Implement and test the solution and escalate as
necessary
• Verify full system functionality and, if
applicable, implement preventative measures
• Document findings, actions, and outcomes
© 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
scenarios
© 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 scenario one
– “I can’t log in!”
• Biggest and most complex scenario
• Log in from other machines
• Attempt to log in yourself and try to ping
• Use ipconfig or ifconfig
© 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 scenario two
– “I can’t get to this Web site!”
• Have user try to reach another Web site
• Try to ping the site by name and IP address
• Determine whether DNS is functioning
• Ping the gateway or proxy server
• Ping other sites
• If other sites reachable, notify problem site owner
• If no sites available, notify your ISP
© 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 scenario three
– “Our Web server is sluggish!”
• Connect from another location
• If connection is also slow, problem with server
• Check server logs for changes
• Run Performance Monitor and compare new
logs with previously established baseline logs
• If connection from other location OK, run
tracert command from user’s computer to
reveal slow hop
© 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 scenario four
– “I can’t see anything on the network!”
• Check connectivity
• Ping a remote system
• Ping loopback address
– If error, run ipconfig /all and fix settings
– If no error, check hardware
» Run utility on NIC
» Test cable
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.
Mike Meyers’ CompTIA Network+® Guide to Managing and
Troubleshooting Networks, Third Edition (Exam N10-005)
• It’s time to escalate!
– Broadcast storms
– Switching (bridging) loops
– Route problems
– Routing loops
– Proxy ARP
© 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 is fun!
– Apply good troubleshooting methodology
– Constantly increase your knowledge
– Become a troubleshooting artist
© 2012 The McGraw-Hill Companies, Inc. All rights reserved.