PING ON GN

PING ON GN3

INTRODUCTION The main purpose of this tutorial is to understand more about the ping utility. If you read this tutorial carefully you will learn more about ping tool which help you in network layer3 troubleshooting . I wish my study on this topic help you to learn more about ping and troubleshooting. This tutorial is good for computer learners , system administrators , network security professionalist and many other who are searching for ping on the google . REQUIREMENTS Gns3 (8.4) Virtual Box Windows XP Windows 7 PHASES PHASE I : DESIGN NETWORK In this phase we design the network  in gns3 . We use one 7200 series router . With one Ethernet switch and two windows operating system (Windows XP and Windows 7 ) .   PHASE II :  CONFIGURE ROUTER In this phase , we configure the  router . Press RETURN to get started. R2#config t Enter configuration commands, one per line.  End with CNTL/Z. R2(config)#int f1/0 R2(config-if)#ip add 10.0.20.1 255.0.0.0 R2(config-if)#no shut R2(config-if)#exit R2(config)# *Dec  3 02:12:13.383: %ENTITY_ALARM-6-INFO: CLEAR INFO Fa1/0 Physical Port Administrative State Down *Dec  3 02:12:14.383: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/0, changed state to up R2(config)#ip dhcp pool hackingDNA R2(dhcp-config)#network 10.0.20.0 255.0.0.0 R2(dhcp-config)#network 10.0.20.0 R2(dhcp-config)#default-router 10.0.20.0 R2(dhcp-config)#exit R2(config)#exit R2# PHASE III : TESTING In this testing phase we perform ping utility in windows platform . We perform this tool to test the layer 3 connectivity  between two devices . PING TEST In our first test ,we use ping utility to test our layer 3 connectivity , and in the image its shows our system is up on the network . In this image , when the source (10.0.0.1/XP) sends the ICMP echo messages then the destination (10.0.0.2/Win7) also reply with ICMP echo reply messages. This only  happen when there is no problem in the network . See the below image for more details -  Image 1 : Image 2 : Example 2 :  Request Time Out In our example we shutdown the router interface , now this causes destination to be unreachable . And when we ping the router (10.0.20.1) address it will reply with Request Timeout messages . See the below image for more details –  PING COMMAND OPTIONS -t  : Sends continuous ICMP echo request to the destination . Use Ctrl + c to abort .   Send No. of Echo request –n count : Sends a specific number of ICMP echo request . If you not enter number with this option then it will send only 4 echo request ( which is by default set ). SEND SPECIFIC SIZE PACKETS EXAMPLE 1 : –l  size : Here you specifies the size of the Icmp echo request in bytes .If you not enter any size it will send by default 32 bytes size packet . Below example image  shows you two things – 1) Packet Size ( In bytes ) , 2) Packet loss (25%) PACKET SIZE : In the below example  you can see we send a echo request message which  has a size of 5000 bytes . We can do this only with the  “ –l “ option . Its amazing . See the other examples of packet size . PACKET LOSS : Another most important , you will see lots of time that whenever you ping the destination , one of the packet will lost . And this is due to the source and possible intermediate device were performing the ARPs  to find the MAC addresses See the below example image for more details – EXAMPLE 2 :  VALID RANGE This example has its story . See the below example image , first we send the echo request packet with the packet size of 55000 bytes , can you see the image , its too big packet . Then we send 65000 bytes of echo request to the destination ( 10.0.0.2/Win7) and at the last as we send the 75000 size of echo request then we fail to send and the reason is range . So my friends when you are sending big-big packets size on the network , just remember the range i.e  from 0 – 65500. Hope you will learn a lot from this example . See the below image for more details - TROUBLESHOOTING WITH PING EXAMPLE : The scenario is this , I try to ping destination (10.0.0.2/Win7) address but its not pinging ? Troubleshoot : Lets check out Loopback first . OK loopback  is working fine , the problem is something else .  CHECK IPCONFIGURATION Ok I got it , the problem is with the TCP/IP services , I recognize this with a simple command “ ipconfig “which shows no Windows IP configuration . And when I open the Local Area Connection Properties , you can see “ Internet Protocol (TCP/IP ) service is not selected . That is why Windows XP (10.0.0.1) is not able to ping the  destination address ( 10.0.0.2/Win7). See the below image for more details - AFTER TROUBLESHOOTING Here you can see after selected the TCP/IP checkbox , our windows xp will get the new ipv4 address(10.0.0.3) from the router . And when we ping the destination (10.0.0.2/Win7) again , it reply echo messages . It means our troubleshooting is successfull. See the below image for more details – may be you will also face problem like this in your office , home  or anywhere .  AT THE END If you like this tutorial then recommend this or share this post with your friends . Also join us on  facebook , leave your messages on facebook , it will help us . Thank you !                                                                     THIS TUTORIAL IS JUST FOR EDUCATIONAL PURPOSE ONLY /-