Is it commonplace / accepted to change an existing CIDR prefix to meet certain network requirements? [duplicate]

This question already has an answer here:

Say for example, you have an IP address with a CIDR prefix of /27 (mask of and are required to create 4 subnets each with an equal amount of usable host addresses, would it be commonplace / accepted to adjust the prefix to /26 (using only 2 additional bits, leaving 6 for the Host ID) to allow for 4 subnets, each with 62 (60 usable addresses)?


Is it just a case of when a prefix is already set (in this case /27) you simply “get what your given” and utilise only 4 of the possible 8 subnets that can be created with the additional 3 bits and have 4 subnets, each with 32 (30 usable addresses)?

I understand the prefix denotes how many bits are considered significant for the network address with the remainder allocated for the host / node.

Thanks in advance, I am quite new to networking but feel like common sense might apply in this case?

I haven’t to been able to find anything that confirms or denies the possibility of doing this when required.

Leave Your Comment

Leave a Reply

%d bloggers like this: