- What's New
- Function Overview
- Service Overview
- Billing
-
Getting Started
- Using a Public NAT Gateway to Enable Servers to Share One or More EIPs to Access the Internet
- Using a Public NAT Gateway to Enable Servers to Be Accessed by the Internet
- Using a Private NAT Gateway to Connect Cloud and On-premises Networks
- Using Multiple Public NAT Gateways Together in Performance-Demanding Scenarios
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User Guide
- Public NAT Gateways
- Private NAT Gateways
- Permissions Management
- Tag Management
- Managing Quotas
- Monitoring
- Auditing
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Best Practices
- Enabling Private Networks to Access the Internet Using a Cloud Connection and SNAT
- Using a Public NAT Gateway and Direct Connect to Accelerate Internet Access
- Using a Private NAT Gateway and Direct Connect to Enable Communications Between a VPC and an On-premises Data Center
- Using a Public NAT Gateway and VPC Peering to Enable Communications Between VPCs and the Internet
- Preserving Your Network with NAT Gateways During Cloud Migration
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API Reference
- Before You Start
- API Overview
- Calling APIs
- APIs of Public NAT Gateways
- APIs for Private NAT Gateways
- Application Examples
- Permissions Policies and Supported Actions
- Appendixes
- Out-of-Date APIs
- SDK Reference
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FAQs
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Public NAT Gateways
- What Is the Relationship Between a VPC, Public NAT Gateway, EIP Bandwidth, and ECS?
- How Does a Public NAT Gateway Offer High Availability?
- Which Ports Cannot Be Accessed?
- What Are the Differences Between Using a Public NAT Gateway and Using an EIP for an ECS?
- What Should I Do If I Fail to Access the Internet Through a Public NAT Gateway?
- Can I Change the VPC for a Public NAT Gateway?
- Does Public NAT Gateway Support IPv6 Addresses?
- What Security Policies Can I Configure to Implement Access Control If I Use a Public NAT Gateway?
- What Can I Do If Connection Between My Servers and the Internet Fails After I Add SNAT and DNAT Rules?
- Can a Public NAT Gateway Limit the Bandwidth of a Server?
- What Can I Do If the Number of Lost Packets of a Public NAT Gateway Exceeds the Threshold (or EIP Port Allocation Exceeds the Threshold)?
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Private NAT Gateways
- How Do I Troubleshoot a Network Failure After a Private NAT Gateway Is Configured?
- How Many Private NAT Gateways Can I Buy in a VPC?
- Can I Increase the Numbers of SNAT and DNAT Rules Supported by a Private NAT Gateway?
- Can Private NAT Gateways Translate On-premises IP Addresses Connected to the Cloud Through Direct Connect?
- What Are the Differences Between Private NAT Gateways and Public NAT Gateways?
- Can a Private NAT Gateway Be Used Across Accounts?
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SNAT Rules
- Why Do I Need SNAT?
- What Are SNAT Connections?
- What Is the Bandwidth of a Public NAT Gateway That Is Used by Servers to Access the Internet? How Do I Configure the Bandwidth?
- How Do I Resolve Packet Loss or Connection Failure Issues When Using a NAT Gateway?
- What Should I Do If My ECS Fails to Access a Server on the Public Network Through a Public NAT Gateway?
- What Are the Relationships and Differences Between the CIDR Blocks in a NAT Gateway and in an SNAT Rule?
- DNAT Rules
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Public NAT Gateways
- Videos
- Glossary
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More Documents
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User Guide (ME-Abu Dhabi Region)
- Overview
- Getting Started
- Managing NAT Gateways
- Managing SNAT Rules
- Managing DNAT Rules
- Monitoring Management
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FAQs
-
NAT Gateway
- What Is the Relationship Between VPC, NAT Gateway, EIP Bandwidth, and ECS?
- How Does A NAT Gateway Offer High Availability?
- Which Ports Cannot Be Accessed?
- What Can I Do If I Fail to Access the Internet Through the NAT Gateway?
- Can I Change the VPC for a NAT Gateway After It Is Created?
- What Is the Quota of the NAT Gateway?
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SNAT
- Why SNAT Is Used?
- What Are SNAT Connections?
- What Is the Bandwidth of the NAT Gateway When a Server Accesses the Internet Through the NAT Gateway? Where Can I Configure the Bandwidth?
- How Do I Resolve Packet Loss or Connection Failure Issues When Using a NAT Gateway?
- What Are the Relationships and Differences Between the CIDR Blocks in a NAT Gateway and in an SNAT Rule?
- DNAT
-
NAT Gateway
- Change History
- API Reference (ME-Abu Dhabi Region)
-
User Guide (Paris Region)
- Overview
-
Getting Started
- Allowing a Private Network to Access the Internet Using SNAT
- Allowing Internet Users to Access a Service in a Private Network Using DNAT
- Allowing On-Premises Servers to Communicate with the Internet
- Using Private NAT Gateways to Enable Communications Between Cloud and On-premises Networks
- Using Multiple Public NAT Gateways Together in Performance-Demanding Scenarios
- Public NAT Gateways
- Private NAT Gateways
- Permissions Management
- Monitoring
-
FAQs
-
Public NAT Gateways
- What Is the Relationship Between a VPC, Public NAT Gateway, EIP Bandwidth, and ECS?
- How Does a Public NAT Gateway Offer High Availability?
- Which Ports Cannot Be Accessed?
- What Are the Differences Between Using a NAT Gateway and Using an EIP for an ECS?
- What Should I Do If I Fail to Access the Internet Through a NAT Gateway?
- Can I Change the VPC for a NAT Gateway?
- What Is the Quota of the NAT Gateway?
- Can I Update NAT Gateways and SNAT Rules?
- Does NAT Gateway Support IPv6 Addresses?
- What Security Policies Can I Configure to Implement Access Control If I Use a NAT Gateway?
- What Can I Do If Connection Between My Servers and the Internet Fails After I Add SNAT and DNAT Rules?
-
Private NAT Gateways
- How Do I Troubleshoot a Network Failure After a Private NAT Gateway Is Configured?
- How Many Private NAT Gateways Can I Create in a VPC?
- Can I Increase the Numbers of SNAT and DNAT Rules Supported by a Private NAT Gateway?
- Can an SNAT Rule and a DNAT Rule of a Private NAT Gateway Share the Same Transit IP Address?
- Can Private NAT Gateways Translate On-premises IP Addresses Connected to the Cloud Through Direct Connect?
- What Are the Differences Between Private NAT Gateways and Public NAT Gateways?
- Can a Private NAT Gateway Be Used Across ?
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SNAT Rules
- Why Do I Need SNAT?
- What Are SNAT Connections?
- What Is the Bandwidth of a NAT Gateway That Is Used by Servers to Access the Internet? How Do I Configure the Bandwidth?
- How Do I Resolve Packet Loss or Connection Failure Issues When Using a NAT Gateway?
- What Should I Do If My ECS Fails to Access a Server on the Public Network Through a NAT Gateway?
- What Are the Relationships and Differences Between the CIDR Blocks in a NAT Gateway and in an SNAT Rule?
- DNAT Rules
-
Public NAT Gateways
- Change History
- API Reference (Paris Region)
-
User Guide (Kuala Lumpur Region)
- Overview
- Getting Started
- Managing NAT Gateways
- Managing SNAT Rules
- Managing DNAT Rules
- Permissions Management
- Monitoring Management
-
FAQs
- NAT Gateway
-
SNAT
- Why Is SNAT Used?
- What Are SNAT Connections?
- What Is the Bandwidth of the NAT Gateway When a Server Accesses the Internet Through the NAT Gateway? Where Can I Configure the Bandwidth?
- How Do I Resolve Packet Loss or Connection Failure Issues When Using a NAT Gateway?
- What Are the Relationships and Differences Between the CIDR Blocks in a NAT Gateway and in an SNAT Rule?
- DNAT
- Change History
- API Reference (Kuala Lumpur Region)
-
User Guide (Ankara Region)
- Service Overview
- Getting Started
- Public NAT Gateways
- Private NAT Gateways
- Permissions Management
- Monitoring
-
FAQs
- Public NAT Gateways
-
Private NAT Gateways
- How Do I Troubleshoot a Network Failure After a Private NAT Gateway Is Configured?
- How Many Private NAT Gateways Can I Create in a VPC?
- Can Private NAT Gateways Translate On-premises IP Addresses Connected to the Cloud Through Direct Connect?
- What Are the Differences Between Private NAT Gateways and Public NAT Gateways?
- Can a Private NAT Gateway Be Used Across Accounts?
- SNAT Rules
- DNAT Rules
- Change History
-
API Reference (Ankara Region)
- Before You Start
- API Overview
- Calling APIs
- APIs for Public NAT Gateways
- Private Nat API
- Permissions Policies and Supported Actions
- Common Parameters
- Change History
-
User Guide (ME-Abu Dhabi Region)
- General Reference
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Application Scenarios
Using SNAT to Access the Internet
If your servers in the VPC require Internet access, you can use the SNAT function to let the servers share one or more EIPs to access the Internet without exposing their IP addresses. In a VPC, each subnet corresponds to one SNAT rule, and each SNAT rule is configured with one EIP. NAT Gateway provides different types of NAT gateways that support different numbers of connections. You can create multiple SNAT rules to meet your service requirements.
Figure 1 shows how servers in a VPC access the Internet using SNAT.
Using DNAT to Provide Services Accessible from the Internet
To allow your servers in a VPC to provide services for the Internet, you can use the DNAT function.
You can associate an EIP with a DNAT rule. As requests with specific protocol and port access the EIP, NAT Gateway forwards the requests to the port of the target server through the mapping between the ports. Besides, NAT Gateway can forward requests on the EIP to your servers based on IP address mapping. NAT Gateway allows multiple servers to share an EIP, which facilitates bandwidth control.
A DNAT rule is configured for one server. If there are multiple servers, you can create several DNAT rules to make the servers share one or more EIPs.
Figure 2 shows how servers in a VPC provide services accessible from the Internet using DNAT. The servers shown in the following figure can be an ECS, a BMS, or a Workspace desktop.
Using SNAT or DNAT to Communicate with the Internet in a High-Speed Way
If a large number of servers that in a private cloud or connect to a VPC through a Direct Connect or VPN connection need to securely access the Internet in a high speed way or to provide services accessible from the Internet, SNAT and DNAT can be used in such scenario. The similar scenarios include Internet, games, e-commerce, and finance.
Figure 3 shows how to communicate with the Internet in a high-speed way.
Configuring Highly Available System Using SNAT
EIPs that bound to resources may be attacked. To improve system reliability, you can add multiple EIPs when configuring an SNAT rule. If one EIP is attacked, services can use another EIP to ensure service running.
If an SNAT rule has multiple EIPs, the system randomly selects an EIP for servers using the SNAT rule to access the Internet.
A maximum of 20 EIPs can be added to each SNAT rule. If EIPs added to an SNAT rule are blocked or unavailable due to attacks, you need to manually delete them from the EIP pool.
Figure 4 shows the networking diagram.
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