- What's New
- Function Overview
- Service Overview
- Getting Started
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User Guide
- Permissions Management
- VPC and Subnet
- Route Table and Route
- Virtual IP Address
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Elastic Network Interface and Supplementary Network Interface
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Elastic Network Interface
- Elastic Network Interface Overview
- Creating a Network Interface
- Viewing the Basic Information About a Network Interface
- Attaching a Network Interface to a Cloud Server
- Binding an EIP to a Network Interface
- Binding a Network Interface to a Virtual IP Address
- Detaching a Network Interface from an Instance or Unbinding an EIP from a Network Interface
- Changing Security Groups That Are Associated with a Network Interface
- Deleting a Network Interface
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Supplementary Network Interfaces
- Supplementary Network Interface Overview
- Creating a Supplementary Network Interface
- Viewing the Basic Information About a Supplementary Network Interface
- Binding or Unbinding an EIP to or from a Supplementary Network Interface
- Changing Security Groups That Are Associated with a Supplementary Network Interface
- Deleting a Supplementary Network Interface
- Network Interface Configuration Examples
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Elastic Network Interface
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Access Control
- Access Control Overview
- Security Group
- Network ACL
- IP Address Group
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VPC Peering Connection
- VPC Peering Connection Overview
- VPC Peering Connection Usage
- Creating a VPC Peering Connection to Connect Two VPCs in the Same Account
- Creating a VPC Peering Connection to Connect Two VPCs in Different Accounts
- Obtaining the Peer Project ID of a VPC Peering Connection
- Modifying a VPC Peering Connection
- Viewing VPC Peering Connections
- Deleting a VPC Peering Connection
- Modifying Routes Configured for a VPC Peering Connection
- Viewing Routes Configured for a VPC Peering Connection
- Deleting Routes Configured for a VPC Peering Connection
- IPv4/IPv6 Dual-Stack Network
- VPC Flow Log
- Elastic IP
- Shared Bandwidth
- Monitoring and Auditing
- Managing Quotas
- Best Practices
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API Reference
- Before You Start
- API Overview
- Calling APIs
- APIs
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API V3
- VPC
- Security Group
- Security Group Rule
- IP Address Group
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Supplementary Network Interface
- Creating a Supplementary Network Interface
- Creating Supplementary Network Interfaces in Batches
- Querying Supplementary Network Interfaces
- Querying the Details of a Supplementary Network Interface
- Querying the Number of Supplementary Network Interfaces
- Updating a Supplementary Network Interface
- Deleting a Supplementary Network Interface
- Network ACL
- Port
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Native OpenStack Neutron APIs (V2.0)
- API Version Information
- Port
- Network
- Subnet
- Router
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Network ACL
- Querying Network ACL Rules
- Querying a Network ACL Rule
- Creating a Network ACL Rule
- Updating a Network ACL Rule
- Deleting a Network ACL Rule
- Querying Network ACL Policies
- Querying a Network ACL Policy
- Creating a Network ACL Policy
- Updating a Network ACL Policy
- Deleting a Network ACL Policy
- Inserting a Network ACL Rule
- Removing a Network ACL Rule
- Querying Network ACL Groups
- Querying a Network ACL Group
- Creating a Network ACL Group
- Updating a Network ACL Group
- Deleting a Network ACL Group
- Security Group
- Application Examples
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Permissions and Supported Actions
- Introduction
- VPC
- Subnet
- Port
- VPC Peering Connection
- VPC Route
- Route Table
- Quota
- Private IP Address
- Security Group
- Security Group Rule
- VPC Tag
- Subnet Tag
- Port (OpenStack Neutron API)
- Network (OpenStack Neutron API)
- Subnet (OpenStack Neutron API)
- Router (OpenStack Neutron API)
- Network ACL (OpenStack Neutron API)
- Security Group (OpenStack Neutron API)
- Precautions for API Permissions
- FAQs
- Out-of-Date APIs
- Appendix
- SDK Reference
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FAQs
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Billing and Payments
- Will I Be Billed for Using the VPC Service?
- Why Is My VPC Still Being Billed After It Was Deleted?
- How Do I View My VPC Bills?
- How Is an EIP Charged?
- How Do I Change My EIP Billing Mode Between Pay-per-Use and Yearly/Monthly?
- How Do I Change the Billing Option of a Pay-per-Use EIP Between By Bandwidth and By Traffic?
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VPCs and Subnets
- What Is Virtual Private Cloud?
- Which CIDR Blocks Are Available for the VPC Service?
- How Many VPCs Can I Create?
- Can Subnets Communicate with Each Other?
- What Subnet CIDR Blocks Are Available?
- Can I Change the CIDR Block of a Subnet?
- How Many Subnets Can I Create?
- How Do I Make the Changed DHCP Lease Time of a Subnet Take Effect Immediately?
- Why Can't I Delete My VPCs and Subnets?
- Can I Change the VPC of an ECS?
- Why Is the ECS IP Address Released After the System Time Is Changed?
- How Do I Change the DNS Server Address of an ECS?
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EIPs
- How Do I Assign or Retrieve a Specific EIP?
- What Are the Differences Between EIP, Private IP Address, and Virtual IP Address?
- Can I Change the Dedicated Bandwidth Used by an EIP to a Shared Bandwidth?
- How Many ECSs Can I Bind an EIP To?
- How Do I Access an ECS with an EIP Bound from the Internet?
- What Is the EIP Assignment Policy?
- Can I Bind an EIP of an ECS to Another ECS?
- Can I Buy a Specific EIP?
- How Do I Query the Region of My EIPs?
- How Can I Unbind an Existing EIP from an Instance and Bind Another EIP to the Instance?
- Can I Bind an EIP to a Cloud Resource in Another Region?
- Can I Change the Region of an EIP?
- VPC Peering Connections
- Virtual IP Addresses
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Bandwidth
- What Are Inbound Bandwidth and Outbound Bandwidth?
- What Are the Differences Between Static BGP and Dynamic BGP?
- How Do I Know If My EIP Bandwidth Limit Has Been Exceeded?
- What Are the Differences Between Public Bandwidth and Private Bandwidth?
- What Bandwidth Types Are Available?
- What Are the Differences Between a Dedicated Bandwidth and a Shared Bandwidth?
- How Many EIPs Can I Add to Each Shared Bandwidth?
- Can I Increase a Yearly/Monthly Bandwidth and Decrease It Later?
- What Is the Relationship Between Bandwidth and Upload/Download Rate?
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Connectivity
- Does a VPN Allow Communication Between Two VPCs?
- Why Cannot I Access Public Websites Through Domain Names or Access Internal Domain Names on the Cloud When My ECS Has Multiple NICs?
- What Are the Priorities of the Custom Route and EIP If Both Are Configured for an ECS to Enable the ECS to Access the Internet?
- Why Are There Intermittent Interruptions When a Local Host Accesses a Website Built on an ECS?
- Why Do ECSs Using Private IP Addresses in the Same Subnet Only Support One-Way Communication?
- Why Does Communication Fail Between Two ECSs in the Same VPC or Packet Loss Occur When They Communicate?
- Why Can't My ECS Use Cloud-init?
- Why Can't My ECS Access the Internet Even After an EIP Is Bound?
- Why Is My ECS Unable to Communicate at a Layer 2 or Layer 3 Network?
- How Do I Handle a BMS Network Failure?
- Why Does My ECS Fail to Obtain an IP Address?
- How Do I Handle a VPN or Direct Connect Connection Network Failure?
- Why Can My Server Be Accessed from the Internet But Cannot Access the Internet?
- Why Can't I Access Websites Using IPv6 Addresses After IPv4/IPv6 Dual Stack Is Configured?
- Why Does My ECS Fail to Communicate with Other After It Has Firewall Installed?
- Routing
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Security
- Does a Modified Security Group Rule or a Network ACL Rule Take Effect Immediately for Existing Connections?
- Why Is Outbound Access on TCP Port 25 Blocked?
- How Do I Know the Instances Associated with a Security Group?
- Why Can't I Delete a Security Group?
- Can I Change the Security Group of an ECS?
- How Do I Configure a Security Group for Multi-Channel Protocols?
- Why Are Some Ports of ECSs Inaccessible?
- Why Is Access from a Specific IP Address Still Allowed After a Network ACL Rule That Denies the Access from the IP Address Has Been Added?
- Why Are My Security Group Rules Not Working?
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Billing and Payments
Show all
Can Subnets Communicate with Each Other?
- Different VPCs cannot communicate with each other, so subnets in different VPCs are isolated from each other.
- Subnets in the same VPC can communicate with each other by default. If network ACLs and security groups are used to protect network security, communications between subnets may be denied by these rules.
- Network ACL: If you associate subnets with different network ACLs and do not add inbound and outbound allow rules, communications between these subnets would fail.
- Security group: If you associate instances (such as ECSs) in a subnet with different security groups and do not add inbound and outbound allow rules, communications between these instances would fail.
If both network ACLs and security groups are configured, traffic preferentially matches the network ACL rules. For details, see Table 1.Figure 1 Communications between subnets in a VPCTable 1 Communication scenarios Scenario
Access Control Configuration
Description
Between subnets
No network ACLs associated
Instances associated with the same security group
- Subnets 3 and 4 are not associated with a network ACL, so they can communicate with each other.
- ECS07, ECS08, ECS09, and ECS10 are associated with the same security group (security group A), so they can communicate with each other.
Subnet associated with the same network ACL
Instances associated with different security groups
- Subnets 1 and 2 are associated with the same network ACL (network ACL A), so they can communicate with each other.
- ECS01 and ECS02 in subnet 1 are associated with security group A, and ECS05 and ECS06 in subnet 2 are associated with security group B. If security groups A and B have no allow rules, ECSs in the two security groups cannot communicate with each other. For example, ECS01 and ECS05 cannot communicate with each other.
Subnet associated with different network ACLs
Subnet 1 is associated with network ACL A, and subnet 5 is associated with network ACL B. If network ACLs A and B have no allow rules, subnet 1 and subnet 5 cannot communicate with each other.
As a result, ECSs in subnets 1 and 5 are blocked from each other even they are in the same security group. For example, ECS01 and ECS 11 cannot communicate with each other.
Within a subnet
Instances associated with different security groups
ECS01 and ECS02 in subnet 1 are associated with security group A, and ECS03 and ECS04 are associated with security group B. If security groups A and B have no allow rules, ECSs in the two security groups cannot communicate with each other even they are in the same subnet (subnet 1). For example, ECS01 and ECS03 cannot communicate with each other.
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