-: Software tools. 2 2
In this video, 3 3
we're going to discuss various software tools 4 4
that are used in troubleshooting 5 5
and configuring our networks and network devices. 6 6
These includes Wi-Fi analyzers, 7 7
protocol analyzers and packet captures, 8 8
bandwidth speed test, port scanners, iPerf, 9 9
NetFlow analyzers, TFTP servers, terminal emulators, 10 10
and IP scanners. 11 11
First, we have wireless analyzers, 12 12
which is a specialized piece of software 13 13
that can be used to conduct wireless surveys 14 14
to ensure you have the proper coverage 15 15
and it helps you prevent any non desired overlap 16 16
between wireless access point coverage zones and channels. 17 17
Now, if you're concerned with the channels and use 18 18
and their signal strength for a given area, 19 19
you can use a view inside of a Wi-Fi analyzer 20 20
to display the SSID of each network detected in that area, 21 21
their relative signal strength 22 22
and the channel they're using. 23 23
Here, you can see that most 24 24
of the 2.4 gigahertz Wi-Fi networks are in use 25 25
and are centered on channel one 26 26
with four others being located on channel six. 27 27
Now channel 11 is not being heavily utilized at all. 28 28
It only has one network called Home. 29 29
This is being located on channel 11 as the home network, 30 30
but there are four other wireless networks 31 31
located at channel nine 32 32
and this could cause interference for both channel six 33 33
and channel 11, 34 34
as you can clearly see they're overlapping frequencies 35 35
on this visualization. 36 36
Now, in addition to this view, 37 37
you can also overlap the coverage zones on a floor plan 38 38
using a Wi-Fi analyzer as part of a wireless site survey. 39 39
This displays the location of the wireless access points 40 40
and the signal strength that's radiating 41 41
from each of those access points. 42 42
In this example, 43 43
you can see the entire office building 44 44
is pretty well covered in Wi-Fi 45 45
as it's shown by the green coverage areas. 46 46
But, there is a smaller area of yellow and orange 47 47
on the left-most wall. 48 48
As you exit the building, 49 49
you'll see more areas of orange and red, 50 50
which indicates areas of lower signal strength too. 51 51
Due to the left wall having a large orange 52 52
and yellow coverage area, 53 53
we may want to suggest adding another access point 54 54
in this area of the building. This would allow us to have 55 55
more wireless networking capabilities 56 56
on that part of the building if we needed to. 57 57
Next, we have protocol analyzers and packet capturing tools. 58 58
Now a protocol analyzer is used to capture 59 59
and analyze signals and data traffic 60 60
over a communication channel. 61 61
In networking, 62 62
we most commonly use a software tool known as Wireshark 63 63
as a protocol analyzer. 64 64
Now a packet capturing tool is going to be used 65 65
to capture packets running over a network connection 66 66
in real time, 67 67
and then save them for later analysis. 68 68
This lets you intercept, log and analyze 69 69
the network traffic and data 70 70
in order to fully identify classify 71 71
and troubleshoot network traffic 72 72
based on its application type, source and destination. 73 73
The tool like Wireshark contains both a protocol analyzer 74 74
and a packet capture functionality, 75 75
making it a great all-in-one tool for you to use. 76 76
Now, Wireshark and other protocol analyzers 77 77
are going to be used to troubleshoot your networks 78 78
when they're experiencing performance issues. 79 79
By using Wireshark, 80 80
you can see a breakdown of each packet that's flowing 81 81
across the network, 82 82
and you could validate if things are operating 83 83
as they should inside your network. 84 84
Cyber security professionals also use Wireshark 85 85
and other packet captures and protocol analyzers 86 86
to be able to trace connections, 87 87
view the contents of suspected network transactions 88 88
and identify bursts of network traffic as either suspicious, 89 89
malicious or benign. 90 90
In addition to Wireshark, 91 91
there are many other protocol analyzers 92 92
out there in the field, 93 93
including Ethereal, Protocol Expert, Netasyst, 94 94
Network Analyzer, Network Instruments Observer, 95 95
LanHound and EtherPeek. 96 96
As for packet capture or packet sniffing tools, 97 97
Wireshark can also perform this function, 98 98
but so does tcpdump, WinDump, PRTG Network Monitor, 99 99
SolarWinds Network Performance Monitor and NetworkMiner. 100 100
Next, we have bandwidth speed testing tools. 101 101
There are several local area network speed test tools 102 102
that exist. 103 103
And there's also many websites that allow you to conduct 104 104
an end to end speed test from your client 105 105
to their internet servers. 106 106
Now a bandwidth speed test tool 107 107
should be more accurately described 108 108
as a throughput test tool though, 109 109
because remember, real-world throughput is the speed 110 110
from your client to the end point device and back. 111 111
Whereas bandwidth is the theoretical limit. 112 112
Essentially, these tools are going to download 113 113
a large random file from a server 114 114
and then turn around and upload it back to that same server. 115 115
During this download and upload process, 116 116
the server measures the amount of time it took to download 117 117
that file and then upload it again. 118 118
This gives you a real world measure of the throughput 119 119
across your network from the client, 120 120
all the way to that server. 121 121
Now, a local area network version of this, 122 122
is going to do the same exact thing, 123 123
but it's going to be conducted by a network appliance 124 124
or a piece of software that you're connect to the network. 125 125
This type of speed test works much the same way 126 126
as the internet speed test I just described, 127 127
except your data transfer only occurs 128 128
over the local area network 129 129
from one client to another client, 130 130
measuring the time it takes to send and receive 131 131
that test file locally. 132 132
If you need to determine if your internet connection 133 133
is performing adequately, 134 134
you can use an internet bandwidth speed tests 135 135
like Speedtest.net. 136 136
If you need to determine 137 137
if your local area network performance is adequate, 138 138
then you're going to use a local area network version of this, 139 139
something like Lan Speed Test or HELIOS's LanTest software 140 140
to meet this need. 141 141
Next, we have port scanners. 142 142
A port scanner is a software tool 143 143
that's used to determine which ports are open on a network. 144 144
Running a port scan on a networker or server, 145 145
is going to reveal which ports are open and listening 146 146
or ready to receive information, 147 147
as well as revealing the presence of security devices, 148 148
such as firewalls that may be present between the sender 149 149
and the target. 150 150
Now a port scan can send a carefully prepared packet 151 151
to each destination port 152 152
and then analyze the response it receives back 153 153
to determine if that port is open, 154 154
closed or filtered. 155 155
Now, there are many different software based 156 156
port scanning tools available. 157 157
What are the most common, 158 158
is Nmap, the network mapper, 159 159
but there are lots of others out there as well, 160 160
including the SolarWinds Port Scanner and LanSweeper. 161 161
Next, we have iPerf. 162 162
iPerf is a software tool that's used 163 163
to gather an active measurement 164 164
of a maximum achievable bandwidth on an IP-based network. 165 165
This is an open source and cross-platform tool 166 166
that can produce standardized performance measurements 167 167
for any given network. 168 168
iPerf has client and server functionality, 169 169
and it can create data streams to measure the throughput 170 170
between the two ends of the connection. 171 171
It can do it in one direction or in both directions. 172 172
Now, iPerf is going to work by creating TCP 173 173
and UDP data streams on an IP network 174 174
and then it's going to measure the throughput of the network 175 175
as it carries that data back and forth. 176 176
Next, we have NetFlow analyzers, 177 177
a NetFlow analyzer is a software tool used 178 178
to perform monitoring, troubleshooting 179 179
and in-depth inspection, interpretation 180 180
and synthesis of traffic flow data. 181 181
By analyzing NetFlow data, 182 182
you can more accurately conduct capacity planning 183 183
and ensure that resources are being appropriately used 184 184
in support of your organizational goals. 185 185
For example, using NetFlow data, 186 186
we can see what types of traffic is consuming 187 187
all the resources on the network. 188 188
Is most of your bandwidth being used by people 189 189
going on Facebook? 190 190
How about Twitter? 191 191
What about Gmail or Exchange? 192 192
Depending on your organizational requirements, 193 193
you may not want a lot of your bandwidth 194 194
being used by people browsing social media, 195 195
but if you're a social media marketing company, 196 196
you would expect to have a large number of people 197 197
on Facebook all day working, 198 198
and that'll be completely appropriate. 199 199
By using NetFlow, you're going to be able 200 200
to see that traffic and determine what looks right to you. 201 201
Now, in addition to looking at specific websites being used, 202 202
you can also look at the application type 203 203
that's generating that traffic 204 204
such as Web, NetBIOS, Voice over IP services, 205 205
ICNP or even BitTorrents. 206 206
But understanding the data flows on your network, 207 207
you can increase your overall performance 208 208
or even block traffic types that are not generating 209 209
any value for your business. 210 210
Next, we have TFTP servers. 211 211
The Trivial File Transfer Protocol or TFTP, 212 212
is a simple protocol for exchanging files 213 213
between two TCP/IP machines. 214 214
TFTP servers are going to be used for simple file transfers 215 215
on our network. 216 216
And they're most commonly used to conduct boot loading 217 217
of remote devices. 218 218
TFTP servers are only going to support two functions. 219 219
They can read files and write files. 220 220
TFTP servers are often going to be used by embedded devices 221 221
or systems that retrieve firmware, 222 222
configuration information or a system image 223 223
during their boot up process. 224 224
In our modern networks, 225 225
many Cisco network devices use TFTP 226 226
to backup their running configurations 227 227
and iOS images to a TFTP server. 228 228
Then, those files can be copied back from the TFTP server 229 229
to a router or switch later if you need them. 230 230
Next, we have terminal emulators, 231 231
a terminal emulator allows a host computer 232 232
to access another computer, 233 233
including remote ones 234 234
through either a command line interface 235 235
or a graphical one using either Telnet or SSH. 236 236
For security purposes, 237 237
we should always be using SSH instead of Telnet though, 238 238
because Telnet does everything in plain text, 239 239
that a terminal emulator is going to allow user 240 240
to access files on the remote computer, transfer files 241 241
between two computers and remotely control 242 242
that remote computer. 243 243
There are many different terminal emulators out there 244 244
on modern workstations 245 245
that allow you to connect to a server or network device. 246 246
But the most popular one on Windows, 247 247
is known as PuTTY. 248 248
PuTTY is a free serial console terminal emulator 249 249
that supports SSH, Telnet, SCP and Rlogin. 250 250
If you need to connect to a switch or a router 251 251
in order to configure it over SSH from a Windows client, 252 252
you're probably going to be using PuTTY. 253 253
Other terminal emulators include Cmder, 254 254
the ZOC terminal emulator and Mintty console emulator. 255 255
If you're working on a Linux client, 256 256
there's many terminal emulators available, 257 257
including ones built into the operating system itself. 258 258
Things like the GNOME terminal, 259 259
the KDE Konsole and xterm. 260 260
If you're working on OSX or a Mac machine, 261 261
there's a built-in terminal program as well called Terminal, 262 262
or you can download other ones like iTterm2, 263 263
MacTerm or Kitty. 264 264
Lastly, we have IP scanners. 265 265
An IP scanner is a software tool 266 266
that's used to search for and detect IP addresses 267 267
and other information related to devices on your network. 268 268
These tools are going to be used to conduct network management 269 269
and to identify any route devices 270 270
that may be connected to your network. 271 271
There are many IP scanners available for us, 272 272
including Nmap, the network mapper, 273 273
Free IP scanner, IP Address Manager, 274 274
PRTG Network Monitor, Angry IP Scanner, 275 275
Network Scanner and the IP Range Scanner by LanSweeper. 276 276
As you may have noticed, 277 277
many of these IP scanners are the exact same tools 278 278
as we discussed for port scanners 279 279
or at least made by the same companies. 280 280
Now, this is because, 281 281
like Nmap, many of these tools can first scan 282 282
for the IP addresses on your network segment, 283 283
and then they can conduct a deeper scan 284 284
against each of those IP addresses to scan the ports 285 285
and the services over those ports. 286 286
For the exam, 287 287
it's important for you to understand 288 288
when you might use a Wi-Fi analyzer, 289 289
a packet analyzer, a packet capture tool, 290 290
a bandwidth speed test tool, a port scanner, 291 291
iPerf, NetFlow analyzers, TFTP servers, 292 292
terminal emulators or an IP scanner. 293 293
If you can remember which tool is used for which thing 294 294
in your network management and troubleshooting, 295 295
you're going to do fine on test day. 296 296
But you do not have to remember all the names 297 297
of all these tools. 298 298
The only ones you'll probably need to know by name, 299 299
are things like Nmap and Wireshark, 300 300
because those are so heavily used 301 301
in network troubleshooting. 302 302
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