> Well, it is Monday morning and what the heck. I'm not sure how it
> goes, but this is how I think it goes, which someone can correct if
> wrong.
> 1 block    
>        192.168.1.0-255       netmask  255.255.255.0

correct

> 2 blocks
>        192.168.1.0-127       netmask  255.255.255.128
>        192.168.1.128-255     netmask  255.255.255.128

correct, but we're not supposed to use the top and bottom nets, are we? :)

> 4 blocks 
>        192.168.1.0-63        netmask  255.255.255.64
>        192.168.1.64-127      netmask  255.255.255.64
>        192.168.1.128-191     netmask  255.255.255.64
>        192.168.1.192-255     netmask  255.255.255.64

no, the netmask for this subnetting arrangement is 255.255.255.192 (/26).

its simple to work out the netmask... remember all we are doing is borrowing
bits from the host addresses to give to the networks.

e.g.

Netmask 255.255.255.192 /26 (11111111.11111111.11111111.11000000)
4 subnets
x.x.x.0      x.x.x.63
x.x.x.64     x.x.x.127
x.x.x.128    x.x.x.191
x.x.x.192    x.x.x.255

taking the last byte, 11000000 = 192.

and for the next network, 8 subnets... we're using a last byte in the netmask
of 11100000 right? :)

so you get a netmask of 255.255.255.224
this gives us 8 networks ( - 2 :)... /27

hope this helps.
Cheers,
Nigel
-- 
Nigel Maddock    | I'm out of my mind, 
[EMAIL PROTECTED]   | but feel free to leave a message... 


--
SLUG - Sydney Linux User Group Mailing List - http://slug.org.au/
More Info: http://slug.org.au/lists/listinfo/slug

Reply via email to