Re: netmask question

[Dan Ritter <dsr@randomstring.org>]

> > Why are you asking these questions?  What's your ACTUAL issue?
> >
> 
> IIRC, last year my ISP gives me 8 IPv4, they said the first is network
> addr, the last is broadcast addr, then I have to calculate the netmask by
> myself.


Well, they told you the additional necessary information: 8
addresses.

2^3 = 8
32 - 3 = 29
They gave you a /29.
The netmask is 255.255.255.248

The package you want to install is sipcalc:

$ sipcalc 123.234.22.1/29

-[ipv4 : 123.234.22.1/29] - 0

[CIDR]
Host address            - 123.234.22.1
Host address (decimal)  - 2078938625
Host address (hex)      - 7BEA1601
Network address         - 123.234.22.0
Network mask            - 255.255.255.248
Network mask (bits)     - 29
Network mask (hex)      - FFFFFFF8
Broadcast address       - 123.234.22.7
Cisco wildcard          - 0.0.0.7
Addresses in network    - 8
Network range           - 123.234.22.0 - 123.234.22.7
Usable range            - 123.234.22.1 - 123.234.22.6


-dsr-