[Swan-dev] addresspool and handing out network/broadcast addresses

[Paul Wouters]

On Sun, 4 May 2014, Lennart Sorensen wrote:

> On Sun, May 04, 2014 at 03:54:55PM -0400, Paul Wouters wrote:
>> I'm suggesting to block *.*.*.0 and *.*.*.255 irrespective of netmask.
>> This of course only prevents network/broadcast addresses for the "class
>> A, B and C" networks. Perhaps we can assume people using differently
>> sized pool know enough about network/broadcast address to exclude these.
>
> If the netmask is /20, then you clearly should NOT block *.*.*.0, only
> the first address in the range.

And hope that every OS that receives a *.*.*.0 will work fine with it?

And that sites or firewalls on the net won't firewall a *.*.*.0 IP address?

Have you ever gotten a DHCP/PPPOE address ending in .0 ?

> Better to assume people DO know what they are doing than to screw things
> up for those that actually do know what they are doing with no way for
> them to fix it.

But in this case it does not screw you up, it just does not use 2x16 IP
addresses of your /20 pool, meaning you will have 4080-32=4048 IP
addresses left for assignments.

Paul