MultiCloud Classroom notes 25/Feb/2024

AWS VPC

This is equivalent to router.
In AWS When we create a vpc it will have a default route table. The default route table will route all internal communication with in a vpc.
We can create route tables and associate them with subnets. The custom route table only can route all the internal communication.

AWS has internet gateway which can be associated with vpc to get two way internet access
Public ips attached to resources will work if there is internet gateway attached and a supporting route table

Create a vpc (10.0.0.0/16) with 2 subnets
- subnet-1 (10.0.0.0/24)
- subnet-2 (10.0.1.0/24)
View the default route table and change the name tag
lets create a open all security group as security group belongs to vpc
Lets create a ec2 instance and attach public ip address and try to connect from your system
At this point of time our network is as shown below
Lets try to ssh into ec2 instance.
Lets attach internet gateway to the vpc and check the ssh again
route and internet gateway are not connected.
Lets change the default route table and create a route to internet gateway
Checking ssh access now and access to internet from ec2 instance.
Lets add one more ec2 instance in subnet 2 without public ip

In rules (firewalls, security groups,…) we can restrict access based on network id not host id

100.100.0.0/16
  100.100.x.x

99.99.99.0/24  => 99.99.99.x


102.101.100.99/32 => 102.101.100.99  

0.0.0.0/0 => x.x.x.x

Azure vnet by default has internet access
Lets create vnet in azure according to the below image
Now create ubuntu vm in subnet 1 with public ip. This vm should be accesible from internet and also should be able to access internet.
Now lets create one more ubuntu vm in subnet 2 without public ip.
How many devices can we connect in azure vnet’s subnet with cidr range 192.168.0.0/24 ?. What are the reserved ips
How many devices can we connect in aws vpc’s subnet with cidr range 192.168.0.0/24 ? What are the reserved ips