Clustering information on ip address failover

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In a same block of IPv4 addresses, can there be same IPs with different submasks?For example, can I have this:

180.70.65.140/26180.70.65.140/25180.70.65.140/24All the 3 addresses above have the same numbers but different subnet mask. Are all the 3 addresses distinct of their own? In other words, 180.70.65.140/25 belongs to User A, 180.70.65.140/25 belongs to lớn User B và 180.70.65.140/24 belongs to User C?

After applying the submask, their network addresses look lượt thích this:

180.70.65.140/26 --> 180.70.65.128/26180.70.65.140/25 --> 180.70.65.128/25180.70.65.140/24 --> 180.70.65.0/24If the addresses are recognised uniquely, how is it so? How would each of the these addresses being recognised to be unique?

I am thinking like once I have 180.70.65.140/26, I can"t reuse the same numbers of 180.70.65.140 again but since classless is meant lớn increase the number of IP addresses, it would vày much if I can"t reuse.


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edited Apr 13, 2017 at 12:14
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asked Nov 16, 2011 at 8:25

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There are numerous reasons, but the simplest is that this will break any routing, because a host will have no way of knowing that they"re going lớn an address on a different network.

So, basically, no. An IP address needs lớn be unique, regardless of subnet.

In other words, if I"m on

192.168.1.1255.255.0.0

And I try to lớn access 192.168.1.2, then it"s going khổng lồ assume it"s on the same subnet.

On a fundamental level, subnets are there khổng lồ separate broadcast domains and improve efficiency. They"re not for sharing IP addresses.


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answered Nov 16, 2011 at 8:27
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DanDan
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As an answer to lớn your question above, the answer is: No you can"t... It is the address itself that must be unique.

The IP(v4) address in each of the three examples would be: 180.70.65.140 (regardless of subnet mask)

The subnet mask can be thought of as: "what defines the limits of my LOCAL network"In order khổng lồ reach any IP outside of this range, the computer would need to liên hệ the "gateway" khổng lồ pass the IP-packet to an external route.

So, for example

180.70.65.140/26 just means that IPs 180.70.65.129 -> 180.170.65.191 are accessible 180.70.65.140/25 just means that IPs 180.70.65.129 -> 180.170.65.255 are accessible 180.70.65.140/24 just means that IPs 180.70.65.1 -> 180.170.65.255 are accessible

Wikipedia has a reasonable links here


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answered Nov 28, 2011 at 23:35
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Steven_WSteven_W
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The way I look at it is , your subnet specifications are like a venn diagram. The bigger subnets incompass the smaller subnets. So one IP could exist in all three subnets. So they vì chưng have be unique if they are all on the same machine & Vlan etc.


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edited Nov 16, 2011 at 9:15
answered Nov 16, 2011 at 8:52
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AndyMAndyM
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