Help Center/ Virtual Private Cloud/ User Guide/ Elastic Network Interface and Supplementary Network Interface/ Network Interface Configuration Examples/ Configuring Policy-based Routes for an ECS with Multiple Network Interfaces/ Overview
Updated on 2024-11-08 GMT+08:00
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Overview

Background

If an ECS has multiple network interfaces, the primary network interface can communicate with external networks by default, but the extended network interfaces cannot. To enable extended network interfaces to communicate with external works, you need to configure policy-based routes for these network interfaces.

Scenarios

This example describes how to configure policy-based routes for an ECS with two network interfaces. Figure 1 shows the networking. The details are as follows:
  • The primary and extended network interfaces on the source ECS are in different subnets of the same VPC.
  • The source and destination ECSs are in different subnets of the same VPC and the two ECSs can communicate with each other through primary network interfaces without configuring policy-based routes.
  • After policy-based routes are configured for the two network interfaces of the source ECS, both the primary and extended network interfaces can communicate with the destination ECS.

You can select a destination IP address based on service requirements. Before configuring policy-based routes, ensure that the source ECS can use its primary network interface to communicate with the destination ECS.

Figure 1 Networking of an ECS with two network interfaces

Operation Guide

You can follow the following operations to configure policy-based routes for Linux and Windows ECSs. For details, see Table 1.

Table 1 Operation instructions

OS

IP Address Version

Description

Linux

IPv4

An ECS running CentOS 8.0 (64-bit):

Configuring IPv4 and IPv6 Policy-based Routes for a Linux ECS with Multiple Network Interfaces (CentOS)

An ECS running Ubuntu 22.04 server (64-bit):

Configuring IPv4 and IPv6 Policy-based Routes for a Linux ECS with Multiple Network Interfaces (Ubuntu)

IPv6

Windows

IPv4

An ECS running Windows Server 2012 (64-bit):

Configuring IPv4 and IPv6 Policy-based Routes for a Windows ECS with Multiple Network Interfaces

IPv6
Parent Topic: Configuring Policy-based Routes for an ECS with Multiple Network Interfaces