0018.EC2 Solution Architect Associate Level

 

EC2 Solution Architect Associate Level

Private vs Public vs Elastic IP

ü   Networking has two type of IPs 1. IPV4 2. IPV6

o    IPV4: 1.160.10.240

o    IPV6: 3ffe:1900:4545:3:200:f8ff:fe21:67cf

ü   In this course, only going to use IPV4

ü   IPV4 is still the most common format used online

ü   Ipv6 is newer and solve problems for the Internet of Things(IoT)

ü   IPV4 allows for 3.7 billion different address in the public space

ü   IPV4: [0-255].[0-255].[0-255].[0-255]

Private vs Public IP (IPV4) Fundamental Difference

Public IP:

ü  Public IP means the machine can be identified on the internet (wwww)

ü  Must be unique access the whole web (not two machines can have the same public IP)

ü  Can be geo-located easily.

Private IP:

ü  Private IP means the machine can only be identified on a private network only

ü  The IP must be unique across the private network

ü  But two different private networks (two companies) can have the same IPs.

ü  Machine connect to www using an internet gateway (a proxy)

ü  Only a specified range of IPs can be used as private IP.

 

Elastic IPs:

ü  When you stop and start an EC2 instance, it can change its public IP. (This is a big problem because every time public IP going to be change for solution of this problem using the Elastic IP).

ü  If you need to have a fixed public IP for your instance, you need an Elastic IP.

ü  An Elastic IP is a public IPv4 IP you own as long as you don’t delete it.

ü  You can attach it to one instance at a time.

ü  With an Elastic IP address, you can mask the failure of an instance or software by rapidly remapping the address to another instance in your account.

ü  By default only 5 Elastic IPs are allowed (You can ask to AWS to increase the Elastic IP)

ü  Overall try to avoid using Elastic IPs

o   They often reflect poor architecture design.

o   Instead, use a random public IP and register a DNS name to it.

 

 

Private vs Public IP (IPv4) In AWS EC2 – Hands On

ü  By Default, your EC2 machine comes with

o   A private IP for internal AWS network

o   A public IP for the www.

ü  When we are doing SSH into our EC2 machines:

o   We can’t use a private IP, because we are not in the same network.

o   We can only use the public IP.

ü  If your machine is stopped and then started the public IP can change.