 So, the next challenge that we have is that the device is connected to the hostile Wi-Fi are still not able to access the institute server ok. So, we did not check the other devices. So, let us go back to a packet reser file and see what what is up with the network devices. So, let me take this one so, the device that we are looking at is a phone which is connected to the Wi-Fi network ok and there is another laptop that is connected to the Wi-Fi network. So, this is it ok. So, yeah let us check if it is yeah so, this is off now let us switch it on. So, physically we have checked that the laptop is on. So, the connection is established with the Wi-Fi router that is fine. So, now let us try to open the web page ok. So, let us just try to open the web page first and see what happens 10 dot 10 dot 10 dot 10 enter ok. It is taking some time that means there is some issue. So, let us go back and try to troubleshoot it. So, let us now try to see if we can connect to the web server via the ping commands ok. So, let us type here PING 10 dot 10 dot 10 dot 10 again we do not have any response here. Now we remember from the previous scenario that what we were trying to do is trying to connect to the gateway and the gateway was 172.16 0.1. So, let us try and see if we can at least get to that. So, that is 172.16 dot 0.1 ping. No, we are not even able to connect to the gateway that means there is a problem on a much lower layer. So, let us go and check where the problem lies. Now let us do this let us also try to do the same thing from the phone to see if it is just the issue of the laptop or it is both of them. No, we are still not able to open the web page from here. So, just to verify if the server is running fine we will go back to the PC and try to open the web page. Yes, the web page is opening from there. That means this PC is able to connect to the server. Now the fault must lie somewhere here. So, either the router is not able router either the connection between the router and switch has some issues or the router has some issues. So, let us try to sort it one by one. So, we see that the router is router 00 interface is connected to switches FA0 slash 24 interface. Now, though I can just look like I mean I can just open the switch and check whether the interface is connected or not what I will do is I will go to the physical topology and try to see how we can look at the interfaces. Okay. So, this is one of the switch and this is the other switch. So, we are this is this is the switch that we are looking for. So, yeah, so this is that particular jack. So, it looks connected and there is a light over here I do not know if you can see it. But if you look closely there is a green colored light over here that means there the activity is fine. So, this is the port number fast Ethernet 0 slash 24. You can see that. Okay. So, the other way of looking at it would be if you can just I mean look at here. So, if you look at number 24 this is on that means the port is fine. So, we what we can do is check the connectivity on the Wi-Fi router. Let us go to the physical port though you cannot check it here in the way we saw on the physical interface. So, what we will have to do is just look at this. So, it is static there is IP address this is there it is connected to the gateway yeah that is it. So, but there is no way we can ping from this kind of a device to the other side, but anyways this is a switch. So, it does not have an IP address. So, now the issue lies somewhere. So, this can this connection is fine. So, now what we will have to see is if there is a issue between this mobile device and the laptop and the Wi-Fi router. Okay. So, how do we check that now? So, let us go to the laptop and see if the laptop is able to communicate to the Wi-Fi router. So, if you open the Wi-Fi router let us look at the address that the Wi-Fi router has that is 192.168.01. So, what we will try to do is try to ping the Wi-Fi router from here. So, we will again use a ping command 192.168.0.1 no we are still not able to connect to the router that means the connectivity between the laptop and the router has some issue. Okay. So, now let us look at what are the settings here 192.168.01 and does the laptop what is the IP address of the laptop. So, you can check it over here. So, now you can see here there is a IP address 169.254.157.83 the point to note here is if you see this series of IP addresses that means your system is not able to obtain a IP address using DHCP and the system itself assigns it IP address of this with the subnet mask of this. So, if you have two systems which are connected to each other and do not assign you do not assign them any IP address they will still be able to communicate because they automatically take an address of this network and both of them will have eventually happen to be on the same network. So, this if you ever see this address as a IP IP address on your system that means your system is not able to obtain a DHCP address. Okay. Let us put it to static and try to get an IP address back now we are still not able now we are still not able to do this. So, a pipa is basically the term used for this address. Now let us see what is the condition on the phone so we will go here and yes even the phone is not able to get an IP address that definitely means that there is some issue with the DHCP now let us go and check the DHCP settings. Okay. So, we have this and okay now here what we can see is there is a wrong subnet mask. So, okay take some time and tell me how many IP addresses will be available if this subnet mask is 252 I mean you can actually see the answer here it says maximum number of user is 1 because I mean actually 252 will give you just 2 IP address which will be the network and the broadcast address so you have no usable IP addresses in this. So, this is a very common thing which happens because this has a tendency when you when you are using a scroll mouse you might have configured the wrong subnet mask by mistake and saved it and hence it is not working. So, let us reconfigure the subnet mask and see so now this is this and we can say let us keep the starting IP address as 100 and we can have some 50 IP addresses that you can assign. So, here you can see starting IP address 192.168.0.100 you can assign IP address to 50 users and this is all set. So, let us go back save these settings these settings have been saved we will close this and go back to the laptop. Now let us again try to get a IP address using DHCP yes now we can get a we have got a 192.168.0.105 and our gateway is 192.168.01 let us check if we are getting an IP address on the phone as well yes 192.168.0.106 ok. So, now let us let us try and see if we are able to connect to the Wi-Fi router first. So, we will go to the desktop ok I have to close this go back to command prompt 192.168.0.1 enter yes we are able to come communicate with the Wi-Fi router and are we able to communicate with the gateway yes the hostel gateway is also connected and let us even try to communicate with the web server so, 10.10.10.10 yes we are able to connect to the web server also now let us try to open the website so, we close the terminal sorry command prompt open the web browser then click 10.10.10.10 and yes we are able to open the institute network website. So, we have also fixed the second issue which was with the settings of the DHCP server in the Wi-Fi router. Let us go ahead and check it on the since it is able to get an IP address I am sure it will also be able to open the website we can straight away go and check that so, 10.10.10.10 yes it is able to check. So, now what we saw is so, in this in this particular scenario our approach was so, in this scenario what our approach was we first tried to check the physical connectivity so, we were able to first create a subsystem so, which was our subsystem so, what we have is this PC is working and it is connected to the switch that means, if we disconnect the network from here I mean this so, the switch the PC and the rest of the network are able to communicate hence the problem lies over this part of the network. So, then we tried to look at the physical connectivity between these two the wire was connected and we could see the light that means, the connectivity was fine and then we tried to check the connectivity between these two. So, as I said so, sometimes checking the wires becomes tedious or especially when you connected via Wi-Fi it becomes difficult to check if your laptop is connected or not all you can do is look at the network status on your laptop or say phone. So, one of the best ways is to ping your Wi-Fi router so, when we tried pinging the Wi-Fi router we realized that the router was not responding hence there was a issue between the connectivity of these two. So, when we looked at the IP address of the laptop we saw it had gotten a PIPA series of an IP address that IP address is only obtained when your laptop is not able to get an IP address from the DHCP server. So, when we check the DHCP server settings there was a wrong gateway that was configured hence the laptop was not able to connect to the Wi-Fi router. So, with this now we have been able to successfully fix the second challenge. Now, let's go towards our third challenge.