How to correctly set the subnet mask installing Linux Ubuntu 20.04 server? ERROR: '172.16.182.216' is not contained in '255.255.255.0/24'

I am not a system engineer or a network expert (I am more a software developer) I am trying to install an Ubuntu Server using static IP address. I am using the information provided by a collegue.

These information are:

• SERVER IP ADDRESS: 172.16.182.216
• SUBNET: 255.255.255.0
• GATEWAY: 172.16.182.1
• DNS: 1.0.0.109 AND 192.168.6.101

I have some problem to set the Subnet mask: first of all I tried to insert the value as provided (255.255.255.0) but the Ubuntu installation prompt says to me that this value should be in CIDR format.

So I tried to insert value like something like 255.255.255.0/24 but then on the IP address I have this error '172.16.182.216' is not contained in '255.255.255.0/24'

I have tried also with other values but I have similar problem. Why? What could be a solution?

1 Answer

It asks for the subnet specification in the 1st field, not the subnet mask.

The subnet is 172.16.182.0 and it uses a 24 bit (255.255.255.0) mask so the CIDR notation for the subnet is 172.16.182.0/24