TCP / IP NETWORKING - 3

TCP / IP NETWORKING INTERVIEW QUESTIONS AND ANSWERS

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21..What are  all the major difference between telnet and ssh?

Telnet

A..Telnet is the joint abbreviation of Telecommunications and Networks and it is a networking protocol best known for UNIX platform.

B..Telnet uses the port 23 and it was designed specifically for local area networks.

C..Telnet is not a secure communication protocol because it does not use any security mechanism and transfers the data over network/internet in a plain-text form including the passwords and so any one can sniff the packets to get that important information.

D..There are no authentication policies & data encryption techniques used in telnet causing huge security threat that is why telnet is no longer used for accessing network devices and servers over public network.

E..On a Linux system, telnet can be easily installed using yum:

SSH

A..SSH stands for Secure Shell and it is now only major protocol to access the network devices and servers over the internet.

B..SSH runs on port 22 by default; however it can be easily changed.

C..SSH is a very secure protocol because it shares and sends the information in encrypted form which provides confidentiality and security of the data over an un-secured network such as internet.

D..Once the data for communication is encrypted using SSH, it is extremely difficult to decrypt and read that data, so our passwords also become secure to travel on a public network.

E..SSH also uses a public key for the authentication of users accessing a server and it is a great practice providing us extreme security.

F..SSH is mostly used in all popular operating systems like Unix, Solaris, Red-Hat Linux, CentOS, Ubuntu etc.

G..We can change the SSH port of our server following the below way:

22..What is network file system?

One of the more useful things that can be done with networking services is sharing files via a network file system. Depending on your network this could be done over the Network File System (NFS), or over the Common Internet File System (CIFS). NFS is typically a 'UNIX' based service. In Linux, NFS is supported by the kernel. CIFS however is not. In Linux, CIFS is supported by Samba.

23..What  is port scanning?

Port Scanning is the act of systematically scanning a computer's ports

24..Explain print queue?

A file  which the print daemon uses so that applications which wish to use the printer do not have to wait until the print job they have sent is finished before they can continue. It also allows multiple users to share a printer.

25..What is Tcpdump?

 A command-line network traffic monitoring tool. It has

been around for a long time and most graphical sniffers depend on it

26..How do find  out the current IP address in IP?

#  /sbin/ifconfig

27..How do find out  the  current default gateway?

#   route –n

28..How to find out the current  hostname?

#  hostnames

29..How to find out the current DNS server?

#  /etc/resolv.conf

30..What is difference between ping and ping6 Commands?

Both ping and ping6 commands are same. Regular ping command works with IPV4 and ping6 works with ipv6 IP address

31..Write the different networks and its  uses?

Network	Uses
ssh	Securely log into a remote host, or run commands on it.
telnet	Log into a remote host (insecure!).
scp	Securely copy files to/from a remote host (batch).
sftp	Securely copy files to/from a remote host (interactive).
ftp	Copy files to/from a remote host (interactive, insecure