Routing Private IP address to Null0

[ttreed]

I am trying to route all private IP address; 10.0.0.0 - 10.255.255.255, 172.16.0.0 -172.31.0.0 and 192.168.0.0 - 192.168.255.255 to null0. For 10.0.00/8 and 192.168.0.0/24 I used the mask of 255.0.0.0 and 255.255.255.0 But I am not sure of the mask that I should use for the 172.16.0.0 - 172.31.0.0

[Maulik Shah]

the mask for the 172 network should be :

172.16.0.0 /12 = 255.192.0.0

[o.hassairi]

i think it's 255.240.0.0

16: 0001 0000

31: 0001 1111

so the second byte is 1111 0000 : 240

u can use subnet calculator too (boson utility)