Can subnet 0 be used?
Table of Contents
Can subnet 0 be used?
Over time, engineers found that the all 0’s subnet wasn’t really used and, if it could be handed out as a useable network, many IP addresses could be changed. An example of an IP address that is using a zero subnet is 10.1. 0.1 with a subnet mask of 255.255. 255.0.
What does IP subnet-zero do?
The ip subnet-zero command provides the ability to configure and route to subnet-zero subnets. Subnetting with a subnet address of zero is discouraged because of the confusion inherent in having a network and a subnet with indistinguishable addresses.
Where are subnets used?
Organizations will use a subnet to subdivide large networks into smaller, more efficient subnetworks. One goal of a subnet is to split a large network into a grouping of smaller, interconnected networks to help minimize traffic.
Is subnet mask still used?
To date, there’s still no answer as to why subnets (as opposed to CIDR) are still in use. There’s two problems with subnet masks: (also applies to CIDR) they introduce possible overlap – ISPs could give out the same IP address as part of different subnets.
Can you use the first and last subnet?
The first and the last subnets always have been usable altough it was discouraged by cisco in the past. From IOS 12 version subnet-zero is set by default. For ccna you do count the first and the last too.
What is the last usable host address for subnet 0?
Subnet Cheat Sheet – 24 Subnet Mask, 30, 26, 27, 29, and other IP Address CIDR Network References
| CIDR | Subnet mask | # of usable IP addresses |
|---|---|---|
| /3 | 224.0.0.0 | 536,870,910 |
| /2 | 192.0.0.0 | 1,073,741,822 |
| /1 | 128.0.0.0 | 2,147,483,646 |
| /0 | 0.0.0.0 | 4,294,967,294 |
Why are subnet masks used?
A subnet mask is used to divide an IP address into two parts. One part identifies the host (computer), the other part identifies the network to which it belongs.
Why is subnet mask important?
The purpose of the subnet mask is to split the IP address into the two components. When you combine, using a logical AND, the IP address and the mask you reveal the network address.
How many subnets need to be created from the 172.16 0.0 16 Network?
16 subnets
0.0/16 into 16 subnets with the mask 255.255. 240.0, i.e. 172.16….2.3 Subnets.
| Network Number | First Address | Last Address |
|---|---|---|
| 172.16.0.0 | 172.16.0.1 | 172.16.15.254 |
| 172.16.16.0 | 172.16.16.1 | 172.16.31.254 |
| 172.16.32.0 | 172.16.32.1 | 172.16.47.254 |
| 172.16.48.0 | 172.16.48.1 | 172.16.63.254 |
Which octet is subnet?
A subnet mask is a four-octet number used to identify the network ID portion of a 32-bit IP address.