/How to be a network adminstrator – II

How to be a network adminstrator – II

We will begin  network admin package 2 , Check the first package here :
 Agenda for this package :

  • $$ netstat
  • $$ ifstat
  • $$ tcpdump
  • $$ dhclient
  • $$ nmap
  • $$ telnet
  • $$ ssh
  • $$ minicom
  • $$ ftp
  • $$ wget
  • $$ showmount

 
1- netstat

  • ** Function : used to display network connections , information , else ..
  • ** Syntax :

$netstat [option]
hint : option like [-r] [-s] ,make view of info page
 
example

 

netstat without options used to display all active localhost connections.
 
2- ifstat

  • ** Function : a simple tool to report interface activity
  • ** Syntax :

$ifstat
example

  • ifstat need to install may be by default with system if not make this
    ◦ sudo apt-get install ifstat for debian
    ◦ yum install ifstat

 

3- tcpdump

  • ** Function : tcpdump command is also called as packet analyzer . With tcpdump allow us to capture packets , then we can use it in analyziz ,we can save it in fie with extension .pcap
  • ** syntax :

$tcpdump [option] [argument such as file name with extension type]
 
example
may be say that you don’t have perrmission fot that

  • $ type su
  • $ tcpdump -i eth0   #network interface

  • making tcpdump files

◦ tcpdump -w test.pcap -i eth0
just after this make ls command and see that will make afile called  test.pcap
 
4- dhclient :

  • ** Function : Dynamic Host Configuration Protocol Client , what !!!

it  provides a means for configuring one or more network interfaces using the Dynamic Host Configuration Protocol
 

  • ** Syntax :

# dhclient [optiom] [argument]
 
example :
from abilities of dhclient that its can renews the ip address

  • ** su
  • ** dhclient eth0                #eth0 (my network interface)

 
 
5- nmap : (Short for network mapper)

  • $ Function :  nmap is a network exploration tool and security
  • $ used as port scanner , so what is the mean of port scanner !
  •  
  • $ Port scanner : A software program designed to go through a large listing of interesting ports or all available network ports and probe each port to see if it is available or open and accepting packets.

 
I am not good an asecurity guy so I am not good at this point , but let’s do some with this
 

  • example :

 

notice PORT and STATE .
 
 
6- telnet :
Function : we can use telnet tool to connect to another remote computer .

  • Syntax :

# telnet  [ server name for example ]
this will ask u for >>
                                    username :
                                    password :
 
 
7- ssh : ( secure shell )

  • # Function : is an encrypted protocol and associated program intended to replace telnet . It can also be used for creating secure tunnels .
  • # Syntax :

# ssh [ server name for example]
 
8- minicom

  • # Function : used to connect to serial device such as router and servers such as cisco router for example .

           #  Syntax  :
 minicom >>>> make connection with default serial device
minicom -s Edit minicom settings
 
 
9- ftp : ( file transfer protocol )

  • ** Function : is commonly used for copying files to and from other computers. These computers may be at the same site or at different sites thousands of miles apart.
  • ** Syntax :

$ftp [option] [host]
when type this this will open a shell begin with ftp> we can make ftp command
 

  • this is the list of available command for ftp

 

5

10 – wget : File download utility for Linux systems

  • ** Function : is a file download utility for the command line. It can be used to download files via HTTP and FTP protocols. In the above example, a file is downloaded from a

remote HTTP system and saved in the current directory.

  • ** Syntax :

examples
▪                     wget http://[HOST/FILE]
▪                     wget ftp://[HOST/FILE]