Kafka Network Connection Conditions

A client can connect to a Kafka instance over a public or private network. Notes before using a private network:

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

Table 1 lists how to access a Kafka instance on a client.

**Table 1** Access modes
Mode	How To Do	Reference
Public access	To access a Kafka instance on a client using IPv4 addresses: Enable public access on the Kafka console and configure elastic IPs (EIPs). A client can connect to the Kafka instance through the EIPs. To access a Kafka instance on a client using IPv6 addresses: Enable IPv6 on the Kafka console and add the IPv6 addresses into the shared bandwidth. A client can connect to the Kafka instance over a public network.	Configuring Kafka Public Access
Public access	Configure port mapping using DNAT. The client can connect to the Kafka instance in a public network.	Accessing Kafka in a Public Network Using DNAT
Private access	A client and a Kafka instance are interconnected when they are deployed in a VPC.	-
	When a client and a Kafka instance are deployed in different VPCs of the same region, connect the client and the Kafka instance across VPCs using a VPC endpoint.	Accessing Kafka Using a VPC Endpoint Across VPCs
	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

Before accessing a Kafka instance on a client, configure the following rules in the security group of the instance.

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	Type	Port	Source	Description
Inbound	TCP	IPv4	9094	IP address or IP address group of the Kafka client	Accessing a Kafka instance over a public network (in plaintext)
Inbound	TCP	IPv4	9092	IP address or IP address group of the Kafka client	Accessing a Kafka instance over a private network within a VPC (in plaintext) Accessing a Kafka instance using a peering connection across VPCs (in plaintext)
Inbound	TCP	IPv6	9192	IP address or IP address group of the Kafka client	Accessing a Kafka instance using IPv6 addresses (without SSL) (private or public network)
Inbound	TCP	IPv4	9095	IP address or IP address group of the Kafka client	Accessing a Kafka instance over a public network (in ciphertext)
Inbound	TCP	IPv4	9093	IP address or IP address group of the Kafka client	Accessing a Kafka instance over a private network within a VPC (in ciphertext) Accessing a Kafka instance using a peering connection across VPCs (in ciphertext)
Inbound	TCP	IPv6	9193	IP address or IP address group of the Kafka client	Accessing a Kafka instance using IPv6 addresses (with SSL) (private or public network)
Inbound	TCP	IPv4	9011	198.19.128.0/17	Accessing a Kafka instance using a VPC endpoint across VPCs (in cipher- or plaintext)
Inbound	TCP	IPv4	9011	IP address or IP address group of the Kafka client	Accessing a Kafka instance using DNAT (in cipher- or plaintext)