Google Certified Associate Cloud Engineer 2020

Sign Up Free or Log In to participate!

Google reserves 4 IP address in a subnet

You said that Google reserves 4 IP address in a subnet. Normally in Networking with CIDR we reserve the first IP for the default gateway and the last IP for broadcast. What are the other 2 reserved for by Google and what are they?

2 Answers


You are correct when saying that the first and last addresses are reserved as per normal networking practice, but Google (as well as AWS for that matter) also reserve 2 extra addresses – the second usable address in the range is reserved for the default gateway, and the second last useable address is "reserved by GCP for potential future use". 

This link has a bit more info as well as a really useful table which spells out the reserved IPs and what they are used for: 

(Just scroll down to the "Reserved IPs" section!)

Sign In
Welcome Back!

Psst…this one if you’ve been moved to ACG!

Get Started
Who’s going to be learning?