Kafka Network Connection Conditions

Notes before using a private network:

By default, a client and a Kafka instance are interconnected when they are deployed in the same VPC.
If they are not, you need to interconnect them because of isolation among VPCs.

Table 1 lists how a client can connect to a Kafka instance.

**Table 1** Connection modes
Mode	How To Do	Reference
Private access	A client and a Kafka instance are interconnected when they are deployed in the same VPC.	-
Private access	When a client and a Kafka instance are deployed in different VPCs of the same region, interconnect two VPCs using a VPC peering connection.	"VPC Peering Connection" in Virtual Private Cloud User Guide

Before connecting a client to a Kafka instance, allow accesses for the following security groups.

After a security group is created, its default inbound rule allows communication among ECSs within the security group and its default outbound rule allows all outbound traffic. In this case, you can access a Kafka instance within a VPC, and do not need to add rules according to Table 2.

**Table 2** Security group rules
Direction	Protocol	Port	Source	Description
Inbound	TCP	9092	0.0.0.0/0	Access a Kafka instance within a VPC (without SSL encryption). Access a Kafka instance across VPCs using a peering connection (without SSL encryption).
Inbound	TCP	9093	0.0.0.0/0	Access a Kafka instance within a VPC (with SSL encryption). Access a Kafka instance across VPCs using a peering connection (with SSL encryption).