Basic Network Utilities
You
will use information and technique that are base in part, on certain techniques
anyone can perform on his machine. There are network utilities that you can
execute from a command prompt (windows) or from a shell (Unix/Linux). Many
readers are already familiar with Windows, so the text’s discussion will
execute the commands and discuss them from the Windows command-prompt
perspective. We must stress that all the operating systems have these
utilities. In this section, you will read about IPConfig, ping & tracert
utilities.
IPConfig
When
beginning to su7dy networks, the first thing, you will want to do is to get
information about your own system. To accomplish this fact-finding mission, you
will need to get t a command prompt. In Windows XP or Windows 2000, you can
open the command prompt by performing the following steps:
1.
Open
the Start menu.
2.
Select
Run.
3.
In
the dialog box that open, type cmd and click OK
4.
Type
ipconfig. (you could input the same
command in Unix or Linux by typing in ifconfig once inside the shell.)
5.
Press
the Enter key. You should see something that command prompt will be open on
your system screen.
This
command gives you information about your connection. Important thing is that
you have received your own IP address. The IP address has default gate way,
which creates your connection with other world. IPConfig command is a first step to configure your network system. Most
of the commands that this text will mention, including IPConfig, have several
parameters, or flags, that can be assigned to commands to treat the computer in
a certain way. You can find out what these commands are by typing in the
command, followed by space and then typing in hyphen question marks.
There
are number of options you might use to find out different details about your
system configuration. The moist commonly used method would probably be the
IPConfig/all.
Ping
Another
commonly used command is ping. We
can use Ping to a test packet, or echo packet, that we can know the performance
of packet. Ping is used in earlier hacking technique.
You
that a 32 byte echo packet was send to the destination and returned. The ttl
item means “time to live”. That time unit is how many intermediate measures, or
hops, the packet should take to the destination before giving up. Reminder that
the Internet is a vast conglomerate of interconnected networks. You packet
probably will not go straight to its destination, but will have to take several
hops to get there. Can you type in ping As with IPConfig - ? You can refine
your ping to find out various ways.
Tracert
The
final command we will examine is tracert. This command is basically a “ping
deluxe”. Tracert not only tells you whether the packet got to its destination
and how long it took, but also tells you all the intermediate hops it took to
get there. This utility will very useful to you in future. Illustrates a
tracert to www.yahoo.com. This same command can be
executed in Linus or Unix, but there it is called “traceroute” rather than
“tracert”.
With
tracert, you can see the IP address of each intermediate step listed and how long
it took to get to that step. Knowing the steps required to reach a destination
can be very important, as you will find.
Certainly,
there are other utilities that can be of use to you when working with network
communication. However, these are three basic utilities which are examined by
us. IPConfig, ping, tracert are absolutely essential for a network administrator and you should commit
them to memory.
Other Network Devices
There
are other devices involved in networking that work to protect your computer
from the outside world. Some of these devise I was briefly mention in previous
articles. We will now review a few of
them in more detail. The two most common devices in this category are the
firewall and the proxy server. Basically firewall
is a main barrier between your network and the rest of the Internet. A
personal computer (PC) can be used as a firewall or in many cases; a special
router can function as a firewall. Firewalls, which can be hardware, software
or a combination of both, use different techniques to protect your network, but
the most common strategy is packet filtering. In a packet-filtering firewall,
each incoming packet is examined. Only those packets which are match with your
criteria. (Generally, only those packets are allowed, which are used special
protocol). Many operating systems, such as Windows XP and many Linus
distributions, include basic packet-filtering software with the operating
system.
The
second common type defensive in proxy
server, a proxy server will almost always be another computer. We can use a
computer as proxy server as well as firewall. Proxy server is a way through
which you can connect with other world. A proxy server hides your entire
network from the outside world. Those people who trying hack your system they
can see a proxy server cannot be seen your system. When packets leave your
network, their headers are changed so that the packets contain the return
address of the proxy server. In contrast, the only way to access the outside
world is through a proxy server. Proxy server with firewall is basic network
security. It would frankly be negligent to ever run a network that did not have
a firewall and proxy server.