[Techtalk] Networking tangent: subnets and netmasks

Brenda Bell k15a-list-linuxchix at theotherbell.com
Wed Apr 16 20:41:04 EST 2003

Quoting Michelle Murrain <tech at murrain.net>:

> Reading Mary's query (which I have not a clue how to help) reminded 
> me that I there is one major piece of TCP/IP that I just don't 
> *grok*, although I can muddle through it if I need to: how to talk 
> about subnets in that nomenclature - how that 
> corresponds to a block of IP addresses, and how that connects to the 
> netmask and broadcast addresses.

Really busy day so I got in on this discussion really late.  Bummer, 'cause
I just love this stuff.  Anyway... to add my $.02...

Whether you're just trying to figure out what subnets are all about or
actually need to set up subnets without making any mistakes, the network
calculator at http://jodies.de/ipcalc is very useful, even if it's just to
see what happens.  Scroll to the bottom of the page, enter an Address like, a netmask of 24 and hit the calculate button.  After you have a
grasp on that, try it again but enter a second netmask of 25 (subnets) or
23 (supernet).  The automatic conversion of the bits might help you grok a
little better :)

Also, there's an IP tutorial on my website -- my intent was to get the
newbie to the point they could actually understand the other networking
documents available on the Web.  You'll find it at


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