IPv4 Private Address Space

[Rudy Zijlstra]

Hi

On 11-05-2021 23:38, Louis Garcia wrote:
> According to standards set forth in Internet Engineering Task Force
> (IETF) document RFC-1918, the following IPv4 address ranges are
> reserved by the IANA for private internets,
>
> 10.0.0.0/8 IP addresses: 10.0.0.0 – 10.255.255.255
> 172.16.0.0/12 IP addresses: 172.16.0.0 – 172.31.255.255
> 192.168.0.0/16 IP addresses: 192.168.0.0 – 192.168.255.255
>
> dhcpd does not seem to like subnet/mask combination.
>
>            authoritative;
>            default-lease-time 600;
>            max-lease-time 7200;
>            subnet 172.16.4.0 netmask 255.240.0.0 {
>                        option domain-name-servers 172.16.4.1;
>                        option broadcast-address 172.31.255.255;
>                        option routers 172.16.4.1;
>                        option ntp-servers 172.16.4.1;
>                        range 172.16.4.50 172.16.4.254;
You are using only a /24 (255.255.255.0). Why then the huge netmask 
above? This would cause an enormous memory allocation which seems 
totally uncalled for.

Cheers

Rudy