VPC security groups example

Last published : Jun 11, 2026
A security group acts as a virtual firewall for the instance to control inbound and outbound traffic. Therefore, you must make sure that in cluster configuration, ports are enabled in the security groups so that the VMs can communicate with each others.
Consider an example with two VMs that uses two subnets:
Subnet 1: 172.17.1.0/24
Subnet 2: 172.17.2.0/24
With this setup, the following table describes the inbound rules for a security group.
Inbound rules

 Type                   Protocol     Port range           Source

ALL UDP                  UDP         0-65535             172.17.1.0/24
All UDP                  UDP         0-65535             172.17.2.0/24
This table indicates that the inbound traffic is allowed between the instances that are assigned to the security group.
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