Your router has the IP address of 216.83.11.65/27. You wish to connect
a new system on the network. Which of the following addresses would
you assign to the new system.
A: 216.83.11.45
B: 216.83.11.87
C: 216.83.11.95
D: 216.83.11.96
The answer is B, but I'm not sure why. Can I get a step by step breakdown?
Your host network can chose from all the bits in the IP address, that are not used to define the network.1
So when looking at the Network Configuration you have, your network has the following range (you can use a subnet calculator to get to these values):
216.83.11.65 - 216.83.11.94
This rules out A and D, because you will need a router to get there (since the IP addresses cannot be directly reached within the network).
Your network internal broadcast address will be 216.83.11.95. This rules out answer C, because a host cannot have the broadcast address of your network.
So, only answer B stands.
1 I know that this might not be understandable at all. Cannot do it better. In this case please refer to Wikipedia: Classless Inter-Domain Routing
Related
I am sorry if its basics, but I did not find the appealing answer for it over the Internet.
Why only MAC is used to transfer the packet to a device ? MAC address is only obtained by ARP for a specific IP address. So, why not just let the routers maintain IP addresses of the neighbouring routers and route packets using IP addresses of routers instead of MAC addresses ?
Why not redesign the architecture, to only use IP address for routing as well as moving the packet in the data link layer too ?
Why do we need MAC addresses?" Why can't network devices such as the routers just send the packet to the next router using the router's IP address?
Note : I know that MAC address is used to identify the system in a network. But you see the source never knew the MAC address of receiver. All it knew was its IP address and MAC address of next hop.
I'm reading Data Comm and Networking by Forouzan ( Ed 5) and it says that even routers have an IP address. So why use the mac address at all. The router can store the IP address of the source and route it to the next router .
EDIT : The question that I was getting as suggestion to this one does not answer my query. There are multiple counter points and proof that I have presented here which could have been done which is not answered by the one which is suggested. So please read my question before making any assumptions.
What do you think makes more sense: Having one protocol like Ethernet handle all the layer 2 details so that its layer 3 payload doesn't have to care, or force IP, ARP, WoL, IPX, MPLS, SLPP, and dozens more implement it on their own? The whole purpose of OSI layers is that upper layers need not know all the lower layer's details and lower layers need need not support the upper layer's features.
MAC addresses are used for the layer 2 protocol which encapsulates a layer 3 protocol. If all the necessary features were embedded into IP, then you'd be leaving other protocols to re-implement layer 2 routing on their own. This would be wildly inefficient.
[I did my research]
I read the IPv4 and Subnetting chapters in the CCNA prep material. Watched several youtube videos and read through several forums. However, I still have a small issue because different sources use certain terms interchangeably however I want to be certain and confirm my understanding to avoid confusion.
[The Question]
Q1
Is the network address the same as the node address the same as the network id ?
Q2
Is the host address the same as the host id?
for instance:
in this ip 184.19.39.34 is 184.19 the network address == the node address == the network id?
is 39.34 the host address == the host id?
Thanks alot guys !
Q1: Basically, yes. You should note though that there are different kinds of network addresses such as IP addresses, subnet addresses/prefixes, or MAC addresses. The exact meaning of each term depends on context.
Q2: If the IP address/mask is 184.19.39.34/16 then 184.19.0.0/16 is the subnet address. 39.34 is the host part of the IP address while 184.19 is the network part. The IP address is split into these parts as indicated by the CIDR value or the network mask (255.255.0.0 for /16).
Note that this split is only relevant for routing and on the last hop, so you don't need to know the mask value of a far IP address.
Answer Q1 :
yes, But on as desired of the Mac or virtual IP or a value for the IP
Answer Q2 :
Gluttony complement each other
You can find a detailed answer here :
[https://www.geeksforgeeks.org/ip-addressing-introduction-and-classful-addressing/][1]
I am trying to learn how to calculate IP addresses from CIDR block.
For example, 10.88.135.144/28 or
10.88.135.10010000/28
From what I understand, that means first 28 bits are associated with network address while the rest 4 bits are host addresses. That would result in following IP range:
10.88.135.10010000 - 10.88.135.10011111
The first IP should be 10.88.135.144 and last IP address should be 10.88.135.159
But according to cidr.xyz. The first IP should be 10.88.135.145 and the last one should be 10.88.135.158.
I really can't figure out why. Can anyone explain the reason for me? Thanks!
Generally, the first IP is the network identifier and cannot be assigned to any device.This is used by router or switch on the network.
The last one is the broadcasting IP and cannot be assigned to any device as this IP is used by router or switch on the network to broadcast information.
https://www.quora.com/In-IP-addresses-what-is-meant-by-network-ID-and-host-ID
https://supportforums.cisco.com/t5/wan-routing-and-switching/what-is-broadcast-address/td-p/2494445#messageBodySimpleDisplay_1
Hello Networking Gurus,
I have a question about IP duplication and how this impact the associated switches (layer 2). Sorry, I don't have any resources available to test this. It would be great if someone can shed some lights of their experience on this.
If I have two servers (Linux), say A & B, serving exactly same contents and for some reason they both are assigned same IP address. To be more specific, if A already has an address IP.100 and B has another address IP.200. Now at this point everything seems working and the switch has proper MAC addresses stored. If, later, B also gets the address IP.100, how would this affect the switch's ARP cache? When B gets the new address I assume it broadcasts ARP? to inform the associated switch.
So the question is, Does the switch stores both machines' entries? or overwrites the existing with new? Is there any standard behaviour or proprietary switches reacts differently?
If a client, with no ARP cache, tries to connect to IP.100, which machine would it be forwarded to? A or B or none? If A OR B, can I say from client point-of-view, that there's no outage? (Assume this is a static website, with no login sessions etc)
Feel free to point any relevant documentation.
Thank you in advance.
In theory, you shouldn’t have two hosts talking on the same IP, unless they are participating in routing. Eg any-cast. As things will break.
Each host will have its own MAC address. If the switch is only doing layer two forwarding, then the switch only keeps track of MAC addresses. It is the end hosts or routers that track ARP entries.
If you move IP 100 to B, then the hosts will update their own ARP table.
But if A and B have 100 at the same time, this will cause issues.
Switch will not see any IP's and do not have arp cache for forwarding packets , it will had only mac address table map macs to ports and macs in your case will be unique
I actually think this is how multicast works.
Hosts obtain a multicast address and all of the devices share that same multicast address.
A switch will gather collections of Mac addresses to that same multicast in it's mac table.
I could be wrong though....Still learning.
For a classification project I'm trying to generate a large list of dynamic IP addresses from a single wireless network. However, the only way I've been able to generate these addresses is by connecting a physically new machine to the network, as the wireless network remembers each machine (and so, whenever one machine rejoins the network the IP address remains the same).
For the sake of brevity, I've been looking for a way of automating the process; technically, all I need to do is find a way to simulate being a "new" machine. This way, it would be far easier to generate a list of IP addresses assigned by a single wireless network.
I've had a great deal of trouble finding out how to do this, and it is very possible I may misunderstand how a wireless network assigns IP addresses, etc.
Thanks!
(continuing from the comments above...)
As it turns out, there's no fancy machine learning necessary at all. You can get all the information you need by connecting just once. When you connect to an IP network and are assigned an address, you get both an address and a subnet mask (look it up if you're not familiar with the terms). Given these, a straightforward snippet of bitwise arithmetic will show you whether another address is part of the same network or not:
if ((my_address & subnet_mask) == (unknown_address & subnet_mask)) { ...
where unknown_address is the address you're testing. (This expression can be simplified a bit by applying boolean simplification rules, but this is a form where it's obvious what is happening.)
For example, if you are assigned:
address: 192.168.11.22
subnet: 255.255.255.0
then any other address is part of the same network if it starts with 192.168.11.. Again, the person who set up the network has very deliberately made these choices.
This very much reminds me of the so-called Barometer question, where one of the possible answers is "trading the barometer to the building's superintendent in return for the information wanted".