Hi Saksham,

Always the higher suffix cidr will be in lower suffix cidr.
10.1.1.0/24 will have 256 addresses and 10.1.1.0/25 will have 128 addresses[1].

/25 will be completely in /24 but not wise versa. 

The below are incorrect.
> isNetworkAWithinNetworkB("10.1.1.0/24", "10.1.1.0/25") returns true
> isNetworkAWithinNetworkB("10.1.1.0/22", "10.1.1.0/23") returns true

I think you can change isNetworkAWithinNetworkB method to compare respective ip 
ranges for cidrs.

What about changing method name isNetworkACompletelyWithinNetworkB() ?

[1]https://www.dan.me.uk/ipsubnets?ip=10.1.1.0


Thanks,
Jayapal

On 13-Dec-2013, at 4:49 PM, Saksham Srivastava <saksham.srivast...@citrix.com> 
wrote:

> Hi,
> 
> I encountered a method isNetworkAWithinNetworkB(cidrA, cidrB) in 
> NetUtils.java which should return true if cidrA is a subset of cidrB.
> The method returns flawed output in many scenarios. After unittesting it I 
> found :
> 
> isNetworkAWithinNetworkB("10.1.1.0/24", "10.1.1.0/25") returns true
> isNetworkAWithinNetworkB("10.1.1.0/25", "10.1.1.0/24") returns true
> isNetworkAWithinNetworkB("10.1.1.0/23", "10.1.1.0/22") returns true
> isNetworkAWithinNetworkB("10.1.1.0/22", "10.1.1.0/23") returns true
> 
> Due to this I am able to create VPC tiers with cidr 10.1.0.0/24 even when the 
> VPC super cidr has been defined as 10.1.1.0/25
> IMO the simpler/cleaner way to compare cidrs should be to compare the 
> respective IP ranges. I have an old patch [1] in RB which uses the IP ranges 
> to compare 2 cidrs.
> We could leverage that to replace isNetworkAWithinNetworkB() or in case of 
> any other suggestions please share.
> 
> Thanks,
> Saksham
> 
> [1] https://reviews.apache.org/r/14124/diff/#index_header
> 

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