ADDS Lab Assignment

Active Directory
#1

The lab assignment for installing and setting up Active Directory and promoting a server to a DC has a possibly incorrect instruction. When modifying the server network settings from a DHCP assigned value to a static IP, the instructions say to set the SUBNET mask to 10.0.0.0/8

The server will not accept this subnet value. Actually, after entering the server IP, it auto-suggests a subnet of 255.0.0.0. Taking this suggestion continues the configuration process, and I completed the setup as a result.

1 Like
#2

Hey Richard,

The number 8 after the slash defines the subnet mask as 255.0.0.0. This is referred to as slash notation:

/8 = 255.0.0.0
/16 = 255.255.0.0
/24 = 255.255.255.0
/32 = 255.255.255.255

The /8 means use 8 bits. It basically comes down to math, binary numbers and IP addresses. This is a complicated subject, but the table above can be very helpful. Basically slash notation “10.0.0.0/8” is shorthand for “10.0.0.0, subnet mask 255.0.0.0”.

Checkout this article that explains this in depth (you’ll get an idea for why I said it was complicated): https://www.akadia.com/services/ip_routing_on_subnets.html#:~:text=The%20subnet%20mask%20for%20a,address%20is%20providing%20host%20address.&text=address%20and%20determines%20the%20network%20address%20and%20the%20node%20address.

To truly understand this, you need to understand how to convert IP address to binary numbers and back. The first section of the link above explains that pretty well.