IP ICMP TCP UDP using wireshark

[Music] Hello friends welcome to network Tei in this session I'm going to tell you about these few protocols ipmp works at layer 3 of OSI Network layer TCP UDP works at transport layer layer 4 of The OSI model if we talk about IP it's a 32-bit address assigned to network devices such as laptop IP cameras IP phones uh router switch firewall IP has got two parts header and the actual data so header is the source IP address and the destination IP address actual data is uh also called payload to give you give you an example of Ip let me uh show you this uh software it's called wies shck Network analyzer what's going on behind the scenes when two computers communicate with each other all that communication in the form of Zer ones we can capture in this software so the front end uh like you know what whatever we are doing uh in the browser it's a front end communication to find out the backend communication we can use this piece of software so we have uh uh network issues latency issues in the network we can use this uh to get uh deep details so I am connected to my network by using the wireless Nick and I'm going to double click on this okay so it's not showing any packets right now because there is no communication going on so in this browser I'm going to search for BBC okay let's come back so we can see the packets uh are there so far it has recorded packets 20820 uh 213 uh now what I'm going to do is I'm going to click on this website so the BBC website is open now this is a front end communication let's go and see what's going on at the back end so so far uh 620 631 packets are recorded now I'm going to stop this communication uh by clicking on this red button before talking about IP let me show you something about DNS click on this find a packet in the display filter I'm going this I'm going to change this option to string over here I'm going to search for BBC I clicked on search so again one more filter I'm going to apply with the DNS name so now we can see only the DNS packets right so the first packet it tells me that my laptop with this private IP address it did a DNS cury to to this destination uh you can see this uh cury packet bbc.co.uk the detail of this packet is down there uh it's a DNS cury uh let me go down so it's doing a cury to the bbc.co.uk then the response came back from the public IP address to my laptop that the public IP address uh for the BBC web weite are 212 582 4693 and 69 so these are the two IP addresses of BBC right to double check this we can open command prompt and over here we can do NS lookup IP address of my laptop is private and uh the DNS settings are also local I'm going to change my DNS server of my laptop to the uh public so 8888 is the gole Google DNS server once the server is changed now I'm going to NS lookup for the public IP address 212 582 44114 you can see the BBC website uh this IP address is ma to PBC website now let's come back so this I wanted to tell you about DNS now I'm going to clear this filter from here and this uh BBC now I'm going to to tell you about uh TCP before that I need to find one TCP packet with the application data so here we go look at packet number 15 uh it says under the information this is an application data uh down there are the more details about the packet I click on secure socket layer so that is our data uh in form of http2 so what is secure socket layer uh it is the Technologies technology used to uh build a encrypted link between the web browser and the web server so that the data can be kept private right so this secure socket layer uh it is mapped it is encapsulating into the transmission control protocol uh which is uh layer four of the OSI and in the form of header we have got Source Port destination port this TCP packet got encapsulated into IP and the headed information on this uh layer which is the layer three of OSI uh Network ler the Header information is Source IP and the destination IP this IP got encapsulated uh into ethernet uh which is the uh layer two of The OSI data link layer and the headed information is source Mac address and the destination Mac address then this complete packet entire packet packet uh was transmitted on the wire or the wireless medium and the size of this packet is 99 bytes and if we talk about bits it's 792 let's go back to the main slide now uh now what is icmp it stands for internet control message protocol it is used to test reachability to a remote Network device uh example of uh icmp protocol is Pink ping is a tool used to check if one network device can reach another Network device so to see how we are using icmp we need to uh use the Y shock protocol right y shock software and ping is a front end tool so for example I need to start the new packet capture continue without saving so the new session has started what I'm going to do is I'm going to Ping Google server from here so we can see we are getting response back from the Google server we sent four packets and we received four packets so there is 0% loss let's go back to the Y shock software first let's stop the packet capturing over here in the filter box let's type in icmp so just the icmp packets pop in uh we can see this is the source IP address of my laptop and the destination was 8888 we sent four requests 1 2 3 4 and we got four replies and we can see the protocol used by ping is the icmp uh so what are the devices that works at layer three uh these devices will uh takes the you know uh packet forwarding decisions above the red line we have got few devices this one and this one are the Cisco high-end devices to connect big sites where you know 500 1,000 users are sitting and these devices you know this is a access point having two external antennas this one is also a nice access point of Cisco having internal antennas uh this this is a picture from the back of access point showing you two external antennas two USB ports four Lan ports for the local connectivity uh this port where this white cable is connected is a van Port from uh this port I'm getting internet connectivity the next Port is a console port in order to configure this access point this port is used the next port to the console is uh uh power port so that uh uh using this port power is applied to this unit below the red line we have got multi-layer switches or the the layer three devices uh again this is uh these devices are used to connect uh large sites and to support hundred and thousands of users these exess points are sufficient uh to support uh 50 or less than 50 users moving on to next slide layer four protocols UDP and TCP UDP is a connectionless protocol which means data packets can be sent without warning preparation negotiation there is no handshake or setup just packets of data right UDP is meant for applications where you are more concerned with keeping the stream of information to make sure you you receive every single packet this makes UDP ideal for Real Time application such as voice so a single packet will contain about 10 to 30 seconds of audio right and uh moving on to next one uh it's uh TCP it's it's a connection oriented protocol which means uh form connection between two end points must be established before any data is transmitted TCP guarantees the delivery of data okay so for example pc1 sends a packet uh one to PC2 PC2 receives packet one without error and sends acknowledgement back to pc1 pc1 receives the acknowledgement and proceed with packet two in this example I'm going to show you that uh before transmitting any data TCP needs to the these three steps Sin Sin a and a uh if I come back to V shock might be I can show you about these sync packets if not then I I need to initiate uh New Y shock packet capture okay so we can see one example over here so we sent one synchronization packet from my laptop to this destination we got a response back from the server to my laptop and my laptop finally sent acknowledgement packet and uh uh there is a connection established between my laptop and this destination public destination so this is how TCP works right uh this is a packet capture uh of the this is a packet capture example in this slide uh a brief example again between TCP UDP TCP is slower but reliable transfers typical applications use TCP email web browsing and the unicast application unicast communication is only possible in TCB uh about UDP it's fast but there is no guarantee transfer example of UDP uh is voice and music streaming so all types of communication is possible in this uh I have uploaded this uh PowerPoint SL uh on my website you can find the download link in the description thank you so much guys for watching this video and please don't forget to subscribe my Channel network techi thank you once again friends and have a good time

Channel: Ganesh_prince

Views: 3,449

Keywords: ip, icmp, tcp, udp, osi, tcpip, networking, communication, wireshark, capturing, network, cisco

Id: 12OR6vN0K7w

Length: 12min 15sec (735 seconds)

Published: Sun Mar 19 2017