Take the 2-minute tour ×
Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Considering subnet masks, how many ways can 1 IPv4 address be interpreted?

share|improve this question

closed as not a real question by EEAA, ThatGraemeGuy, Michael Hampton, Tim Brigham, mgorven Mar 12 '13 at 16:40

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

    
You can find a lot of info here: serverfault.com/questions/49765/how-does-ipv4-subnetting-work –  slimsuperhero Mar 12 '13 at 6:56
    
The edit you made actually makes the question less (far, far, far less) clear than it was before. –  HopelessN00b Mar 12 '13 at 20:02
    
how was it clear before? if you read the reasons given for "closed as not a real question"... –  server-builder Mar 13 '13 at 6:52

2 Answers 2

One IP address is one IP address. The subnet mask only defines how large the subnet around the address is (i.e. how many machines are on the LAN).

Netmask and hostmask are technically the same, only using a different notation. A netmask of 255.255.255.0 defines the same subnet as a hostmask of 0.0.0.255, which is the same as a prefix length of /24.

share|improve this answer

Really you are asking how many different subnets might a given IP address belong to, if you don't know the subnet mask. This sounds an awful lot like a homework question.

Anyway, the smallest possible subnet is /32 with a subnet mask of 255.255.255.255. The largest possible subnet is /1 with a subnet mask of 128.0.0.0.

So there are 32 different possible subnet masks, but there are a different number of subnets possible for each mask. However, there are only a certain number of subnets for each size which a given IP address will be valid for. E.g. 1.2.3.4 is not a valid address in the subnet 254.254.254.0/24.

A further complexity will be whether you know that the IP address is assigned to a computer, and isn't therefore a subnet address or broadcast address, or one of the other restricted addresses - this would exclude some subnets that would otherwise be valid.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.