[CLUE-Tech] Network Guru?

[Jef Barnhart]

A) the rules have not changed just the notation.

B) HMM... The setup may know how to parce the notation in setting up the network.

++++++++++++++++++++++++++++++++++++++
I believe that you need to set up the network this way.

12.147.70.88/27
12.147.70.88 with a subnet mask that is 27 bits. This is the CIDR(?) way of doing the network notation. Twentyfour (24) bits will get you 255.255.255.0 . Twentyseven (27) bits will get you 255.255.255.224 .

255.255.255.0     > 11111111.11111111.11111111.11111111.00000000
255.255.255.224 > 11111111.11111111.11111111.11111111.11100000

A neat program that I ran across is cidr. 

jef>$ /usr/local/bin/cidr 14.147.70.88/27

ip address..........:  14.147.70.88
netmask.............:  255.255.255.224

network address.....:  14.147.70.64
broadcast address...:  14.147.70.95

please wait while host addresses are validated...

total host addresses:  30

This is a very helpful program to have around for this stuff. It will compute the broadcast, network, and subnetmask. 

Sorry if I rambled. I got carried away with this.

Jef

On Mon, 17 Dec 2001 11:32:07 -0800 (PST)
Keith Hellman <kehellman at yahoo.com> wrote:

> Hello all, I need the input of a network guru:
> 
> I seem to recall that some of the fundamental rules at the IP layer is
> that:
> *	Every node on a subnet must have all it's network bits set appropriately
> in its IP address.
> *	Node must be to the right of the LSB of the network address
> 
> I've been told (by IT in my org) to use: 12.147.70.88/27 for a little
> embedded device.  This doesn't make sense to me...
> 	12.147.70.88  = 12.147.70.01011000
> network	12.147.70.224 = 12.147.70.11100000
> (last octets in bin, duh..)
> 
> Admittedly my notebook (running SuSE 7.2/kernel 2.4.X) works aok on the
> jack.  But the embedded device (2.0.38 linux kernel) can't even ping or be
> pinged.
> 
> On my development network, I can recreate the problem, and when I switch
> the IP address to include the network bits - everything works AOK.
> 
> So, my questions are:
> A)  Am I way off base here?  Am I thinking circa 80's IP rules and things
> are different now?
> B)  Apparently an implementation has changed in the linux kernel since my
> notebook doesn't complain - is this true?
> 
> Thanks in advance,
> 
> 
> =====
> Keith E. Hellman
> kehellman at yahoo.com
> 
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