search

jsakamoto / ipaddressrange

.NET Class Library for range of IP address, both IPv4 and IPv6.
Mozilla Public License 2.0
368 stars 71 forks source link

When Parsing a IPAddressRange the network and broadcast Addresses should not be included.. #76

Closed RobbyScherpereel closed 2 years ago

RobbyScherpereel commented 2 years ago

Hi,

I saw that wen you are returning an IPAddressRange, you guys are including the network and broadcast addresses. I don't know if this is on purpose, but these addresses are not really usable..

Can you modify this so that they are not included?

192.168.1.0 - 192.168.1.255 shoud rather be 192.168.1.1 - 192.168.1.254. We now have to add an extra if to skip the network and broadcast addresses.

Maybe it is an idea to add a for example IPAddressRange.ToUsableHostIPRange() -> see also https://www.calculator.net/ip-subnet-calculator.html .

image
jsakamoto commented 2 years ago

@RobbyScherpereel Thank you for your proposal! Please let me try to explain this idea.

First, the IPAddresRange class does not represent an IP subnet. It merely represents a range of IP addresses purely. "A range of IP addresses" does not equal "an IP subnet".

For example, let's think about the IP address range 10.0.0.0-10.0.255.255.

If you use this IP address range in the 8bit subnet address world, a broadcast address in this world is 10.255.255.255. So the end of that IP address range 10.0.255.255 is usable for a host.

On the other hand, If you use this IP address range in the 16bit subnet address world, a broadcast address in this world is 10.0.255.255. So the end of that IP address range 10.0.255.255 is not usable for a host.

As you can see above, calculating a broadcast address requires the information that the bit length of a subnet. However, the IPAddressRaneg class does not have such information.

Therefore, producing a method like the ToUsableHostIPRange() is impossible.

Again, the IPAddresRange class merely represents a range of IP addresses purely. There is no restriction involved with subnets.

By the way, you may create an extension method like IPAddressRange ToUsableHostIPRange(this IPAddressRange range, int subnetLength);, and also creating that method by yourself might be easy for you.

Finally, I would like to conclude that I would not implement the feature like the ToUsableHostIPRange() method, at least now.

I hope my conclusion above makes sense to you.

RobbyScherpereel commented 2 years ago

thanks for the explaination. I figured it out already and we are already considering the extension method :)