Subnet Calc is a subnet / ip calculator designed to help network administrators with the time consuming effort of remembering all the subnets that they administer. It will show all details relevant to a subnet, given an IP address and subnet in CIDR notation.
Please feel free to leave comments here if you have used my application and have found it useful – I would very much like as much feedback as possible.
News
- 12/01/2009 – Subnet Calc is mentioned on Softpedia.
- 10/01/2009 – v1.2 released
- 28/11/2008 – v1.1 released
- 20/11/2008 – v1.0 released
- 12/11/2008 – Work has already begun on the next version. This is going to include a simple way to save subnet definitions which will persist between sessions and will also automatically backup with a usual iPhone / iPod backup. Other features may also appear if I can get them ready in time.
- 07/11/2008 – New logo! Check it out below. This will be appearing in future versions.
- 06/11/2008 – Subnet Calc accepted into the app store
Dear Mr. Galloway,
my name is Martin Behrendt, I am a product manager of http://www.apprupt.com. We would like to integrate your app into a number of websites that we partner with.
We are currently focusing on the European market and I think especially Subnet Calc and QuickPass could do very well there.
We deliver a small rev-share to our partners in exchange for their reach. There are several sites I could imagine your apps being offered at.
I could not find any other way to contact you so I am purposely not stretching this email to lengths, although I would surely be glad to explain our company in more detail to you.
Let me know if this sounds interesting enough for you to further communicate.
Also, check out http://www.apprupt.com for more information.
Would be great to hear back from you!
Best,
Martin Behrendt.
Matt,
Regarding the Subnet Calc iPhone app, it looks good and is a breeze to use.
However, I am curious why it calculates the maximum number of available hosts incorrectly. It does not to take account of the Broadcast address.
For example, the opening example network of 192.168.0.0/24 states there are a max of 256 host addresses. With 8 host bits, it should state 254 hosts max (or 255, if host of all 0′s is allowed).
David Stooke
(Cisco Certified Systems Instructor)
Hi David,
Yes I’ve had this asked a few times. I do agree that the “maximum number of hosts” is technically 254 in your example case, but I prefer to think of it as 256 and then take the 2 off in my head. Those 2 IPs are usable in the sense that you might, well, use them. OK you can’t have a host using it as it’s IP address… but…
I think it’s a minor point, but a very good one to make. I’m always looking for feedback and so if there’s anything else then please do just let me know.
Many thanks for using Subnet Calc Pro!
Matt
i AM THINKING OF DEVELOPING AN APP. caN YOU PLEASE ADVISE ME OR PROVIDE SOME HELP?
maNY tHANKS
dr syed
Just got Subnet Calc (lite).
Really lean and nice program! Cool!
I have a small request:
In the lower part the first two datalines are showing
ip …
netmask …
As ‘IP’ is redundant (same as the input field right at the top) and the netmask is “only” the numerical display of the bitmask, I’d like to put in an idea:
Make the lower part (Subnet Calculation) sortable so that anyone can change the order of the rows as he whishes.
Or:
Pls hardcode ‘hostmin’ and ‘hostmax’ as the first two display lines if suggestion 1.) is too complex.
Anyway:
Many thanks for your App!
Regards
Holger
@Holger – Excellent idea. I think I’ll add in the ability to reorder the rows which then gets saved for each time you load the app.
The reason for having IP address again in the calculation section is that when you view in hexadecimal or binary mode then it makes sense to have the IP visible in this notation, but to still be able to enter it in the standard dotted decimal manner.
Great app. Two comments…hosts are hosts not broadcasts…please allow entering of subnets in both prefix and netmask octet notations.
@Jason – Yes I am planning that sort of feature for future releases. Thanks for the comments and for using the app.
Hi Matt,
Fantastic, simple and elegant app.
Definitely makes subnet calculations a breeze. Mind you, I still prefer to manually calculate them so that I don’t loose that skill. Having this apps allows me to check that I’ve got it right.
I was going to mention the Maximum hosts being miscalculated (includes Network and Broadcast addresses), but someone else has beaten me to it.
As for being able to enter the subnet mask in dotted-decimal instead of the shorthand method, I don’t see the point in implementing it as you can see what the d-d mask is at the same time as selecting the # of bits.
169.254.0.0/16 is considered a “link-local” address range by the Cisco CCNA v4.0 courseware – Windows PC’s (WinXP and above certainly) and possibly those running better OS’s default to an address in this range when DHCP fails.
192.0.2.0/24 is also reserved, for testing purposes and use in documentation (alongside example.com) and is classed as “Test-Net” by the same courseware.
@Tim – thanks for the comments. Yes I should add in the link-local and test-net ranges you’re right. I’ll add that to my ever growing list of things to do with Subnet Calc.
With regard the maximum hosts, I feel it’s a matter of preference. I like to know how many IPs a certain range gives me – including the network and broadcast. Having to subtract 2 to find the number of “usable” hosts is fine I feel. However, given the amount of call for it to display the value as “2^(32-CIDR) – 2″, I feel I should do that in the next release.
Thanks again for your comments – I appreciate it a lot!
Hi
Great tool, realy great tool!
For me the free version is perfect expept for one thing; I don’t need to see the hex-code or the bit-nr. This would make the free version more simplier and you have more reason to pay for the Pro!
Or at least give me this as an option in the free version.
or have Free, Standard (1 USD) and Pro (3 USD or what ever)
Rickard
Sweden
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