[ale] Networking question

[brucelists at bellsouth.net]

Using 192.168.0.1 with a 255.255.255.192 mask (26 bits) gives you:

network 192.168.0.0
broadcast 192.168.0.63
hosts 192.168.0.1 - 62

network  192.168.0.64
broadcast 192.168.0.127
hosts 192.168.0.65 - 126

network 192.168.0.128
broadcast 192.168.0.191
hosts 192.168.0.129 - 190

network 192.168.0.192
broadcast 192.168.0.255
hosts 192.168.0.193 - 154

I cheated. I used an online IP calculator. I'm trying to learn this stuff again to renew my CCNA (I let it lapse, and have been hitting the books. I HATE IP subnetting).

Now - if you are using private addresses as above, why go to all that hassle? For my lab at home I'm using 192.168.1.0 for DMZ, 192.168.2.0 for home LAN, and 192.168.10.0, 20.0, 30.0, 40.0, 50.0 and 60.0 for a Cisco lab. I'm math lazy, and just use the 255.255.255.0 mask. 

I can see being very careful of publicly routable IP addresses, but anything behind a firewall and in the 10.0.0.0  - 10.255.255.255, 172.16.0.0 - 172.31.255.255 and 192.168.0.0 - 192.168.255.255 ranges are up for grabs! (well, so long as they are behind firewalls or routers and you don't try to route them publicly)

Bruce

> 
> From: Trey Sizemore <trey at fastmail.fm>
> Date: 2005/07/22 Fri PM 09:48:44 EDT
> To: Atlanta Linux Enthusiasts <ale at ale.org>
> Subject: [ale] Networking question
> 
> I have a networking conceptual problem.  Suppose I plan to use the
> 192.168.0.1 network for an intranet.  With a default network mask of
> 255.255.255.0 I would have 254 host addresses available.
> 
> With a 25-bit mask (255.255.255.128) I would be able to have 2
> subnetworks and each would be able to have 126 addresses available.  The
> host ranges for each would be 192.168.1.1 - 192.168.1.127 and
> 192.168.1.129 - 192.168.1.255.
> 
> Now, with a 26-bit mask (255.255.255.192) I understand that I would be
> able to have 4 subnets and each would support 62 hosts, but what would
> the host ranges be?
> 
> This concept of subnetworks is kicking my butt.
> 
> Thanks.
> 
> -- 
> Cheers,
> Trey
> ---
> 
> Thieves respect property;
> they merely wish the property to become their property
> that they may more perfectly respect it.
> -- G.K. Chesterton, "The Man Who Was Thursday" 
> 
> 9:42pm up 12:29, 4 users, load average: 0.00, 0.00, 0.00 
> Linux salamander 2.6.11.4-21.7-default #1 Thu Jun 2 14:23:14 UTC 2005
> i686 i686 i386 GNU/Linux
> 
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