System information

Manual:Tools/Packet Sniffer
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References
[1] http:/ / www. wireshark. org/
Manual:Troubleshooting tools
Troubleshooting tools
Before, we look at the most significant commands for connectivity checking and troubleshooting, here is little
reminder on how to check host computer's network interface parameters on .
The Microsoft windows have a whole set of helpful command line tools that helps testing and configuring
LAN/WAN interfaces. We will look only at commonly used Windows networking tools and commands.
All of the tools are being ran from windows terminal. Go to Start/Run and enter "cmd" to open a Command window.
Some of commands on windows are:
ipconfig – used to display the TCP/IP network configuration values. To open it, enter "ipconfig" in the command
prompt.
C:\>ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : mshome.net
Link-local IPv6 Address . . . . . : fe80::58ad:cd3f:f3df:bf18%8
IPv4 Address. . . . . . . . . . . : 173.16.16.243
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 173.16.16.1
There are also a variety of additional functions for ipconfig. To obtain a list of additional options, enter
"ipconfig /?" or “ipconfig -?”.
netstat – displays the active TCP connections and ports on which the computer is listening, Ethernet statistics, the IP
routing table, statistics for the IP, ICMP, TCP, and UDP protocols. It comes with a number of options for displaying
a variety of properties of the network and TCP connections “netstat –?”.
nslookup – is a command-line administrative tool for testing and troubleshooting DNS servers. For example, if you
want to know what IP address is "www.google.com", enter "nslookup www.google.com" and you will find that there
are more addresses 74.125.77.99, 74.125.77.104, 74.125.77.147.
netsh – is a tool an administrator can use to configure and monitor Windows-based computers at a command
prompt. It allows configure interfaces, routing protocols, routes, routing filters and display currently running
configuration.
Very similar commands are available also on unix-like machines. Today in most of Linux distributions network
settings can be managed via GUI, but it is always good to be familiar with the command-line tools. Here is the list of
basic networking commands and tools on Linux:
ifconfig – it is similar like ipconfig commands on windows. It lets enable/disable network adapters, assigned IP
address and netmask details as well as show currently network interface configuration.
iwconfig - iwconfig tool is like ifconfig and ethtool for wireless cards. That also view and set the basic Wi-Fi
network details.
nslookup – give a host name and the command will return IP address.