- 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
-
User Guide
- Public NAT Gateways
- Private NAT Gateways
- Permissions Management
- Tag Management
- Managing Quotas
- Monitoring
- Auditing
-
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
-
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- Out-of-Date APIs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
-
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 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?
-
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
-
Public NAT Gateways
- Videos
- Glossary
-
More Documents
-
User Guide (ME-Abu Dhabi Region)
- Overview
- Getting Started
- Managing NAT Gateways
- Managing SNAT Rules
- Managing DNAT Rules
- Monitoring Management
-
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?
-
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 ?
-
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
- Scenarios
- Operation Process
- Step 1: Buy an EIP
- Step 2: Buy a Public NAT Gateway
- Step 3: Add a Default Route Pointing to the Public NAT Gateway
- Step 4: Add a DNAT Rule
- Step 5: Verify that the DNAT Rule Has Been Added
- Step 6: Verify that Servers in a VPC Can Be Accessed from the Internet Through the NAT Gateway
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Using a Public NAT Gateway to Enable Servers to Be Accessed by the Internet
Scenarios
When one or more servers in a VPC need to provide services accessible from the Internet, you can add DNAT rules for a public NAT gateway, as introduced in this section.
Operation Process
Procedure |
Description |
---|---|
Buy an EIP. |
|
Buy a public NAT gateway. |
|
Step 3: Add a Default Route Pointing to the Public NAT Gateway |
Add a route table. |
Add DNAT rules for the public NAT gateway so that servers in specific CIDR blocks share EIPs to access the Internet. |
|
Check whether the DNAT rule has been added. |
|
Step 6: Verify that Servers in a VPC Can Be Accessed from the Internet Through the NAT Gateway |
Verify that servers for which the DNAT rules are applied can be accessed by a client on the Internet. |
Step 1: Buy an EIP
- On the Assign EIP page, set the EIP name to EIP-A.
You can configure other EIP parameters as required. For details, see .
Step 2: Buy a Public NAT Gateway
- On the Create Public NAT Gateway page, configure required parameters.
Table 1 Descriptions of public NAT gateway parameters Parameter
Example
Description
Region
CN North-Beijing4
The region where the public NAT gateway is located.
Specifications
Small
The specifications of the public NAT gateway.
The value can be Extra-large, Large, Medium, or Small. To view more details about specifications, click Learn more on the page.
Name
public-nat-01
The name of the public NAT gateway. Enter up to 64 characters. Only letters, digits, underscores (_), hyphens (-), and periods (.) are allowed.
VPC
vpc-A
The VPC that the public NAT gateway belongs to.
The selected VPC cannot be changed after you create the public NAT gateway.
NOTE:
To allow traffic to pass through the public NAT gateway, a route to the public NAT gateway in the VPC is required. When you create a public NAT gateway, a default route 0.0.0.0/0 to the public NAT gateway is automatically added to the default route table of the VPC. If the default route 0.0.0.0/0 already exists in the default route table of the VPC before you create the public NAT gateway, the default route that points to the public NAT gateway will fail to be added automatically. In this case, perform the following operations after the public NAT gateway is successfully created: Manually add a different route that points to the gateway or create a default route 0.0.0.0/0 pointing to the gateway in the new routing table.
Subnet
Subnet-A01
The subnet that the public NAT gateway belongs to.
The subnet must have at least one available IP address.
The selected subnet cannot be changed after you create the public NAT gateway.
The NAT gateway will be deployed in the selected subnet. The NAT gateway works for the entire VPC where it is deployed. To enable communications over the Internet, add SNAT or DNAT rules.
Advanced Settings (Optional)
-
Click the drop-down arrow to configure advanced parameters of the public NAT gateway.
SNAT Connection TCP Timeout (s)
900
The timeout period of a TCP connection established using the SNAT rule. If no data is exchanged within this period, the TCP connection will be closed.
Value range: 40 to 7200
SNAT Connection UDP Timeout (s)
300
The timeout period of a UDP connection established using the SNAT rule. If no data is exchanged within this period, the UDP connection will be closed.
Value range: 40 to 7200
SNAT Connection ICMP Timeout (s)
10
The timeout period of an ICMP connection established using the SNAT rule. If no data is exchanged within this period, the ICMP connection will be closed.
Value range: 10 to 7200
TCP TIME_WAIT (s)
5
How long the side that actively closed the TCP connection is in the TIME_WAIT state.
Value range: 0 to 1800
Description
Not required
Supplementary information about the public NAT gateway. Enter up to 255 characters. Angle brackets (<>) are not allowed.
Tag
Not required
The identifier of the public NAT gateway. A tag is a key-value pair. You can add up to 20 tags to each public NAT gateway.
- Click Create Now. On the page displayed, confirm the public NAT gateway specifications.
- If you do not need to modify the information, click Submit.
On the Public NAT Gateways page, you can view the created public NAT gateway in the list.
Step 3: Add a Default Route Pointing to the Public NAT Gateway
- On the Route Tables page, click Create Route Table in the upper right corner.
VPC: Select the VPC that the public NAT gateway belongs to.
- After the custom route table is created, click its name. The Summary page is displayed.
- Click Add Route and configure parameters as follows:
Destination: Set it to 0.0.0.0/0.
Next Hop Type: Select NAT gateway.
Next Hop: Select the created NAT gateway.
Figure 1 Add Route - Click OK.
Step 4: Add a DNAT Rule
- On the displayed page, click the name of the public NAT gateway on which you need to add a DNAT rule.
- On the public NAT gateway details page, click the DNAT Rules tab.
- Click Add DNAT Rule.
- Configure required parameters. For details, see Table 2.
Table 2 Descriptions of DNAT rule parameters Parameter
Example
Description
Scenario
VPC
Select VPC if your servers in a VPC will use the DNAT rule to provide services accessible from the Internet.
Different servers in a VPC can share the same EIP to provide services accessible from the Internet.
Port Type
Specific port
The port type.
- All ports: All requests received by the gateway through all ports over any protocol will be forwarded to the private IP address of your server.
- Specific port: Only requests received from a specified port over a specified protocol will be forwarded to the specified port on the server.
Protocol
TCP
The protocol can be TCP or UDP. This parameter is available if you select Specific port for Port Type. If you select All ports, this parameter is All by default.
Public IP Address Type
EIP
The EIP of the public NAT gateway.
Outside Port
80-100
The port of the EIP used by the NAT gateway. The port number ranges from 1 to 65535.
You can enter a specific port number or a port range, for example, 80 or 80-100.
Instance Type
Server
The instance type for which the DNAT rules are applied.
NIC
-
The network interface of the server.
Inside Port
80-100
The port of the server that provides services accessible from the Internet through the DNAT rule. This parameter is available if you select Specific port for Port Type. The port number ranges from 1 to 65535.
You can enter a specific port number or a port range, for example, 80 or 80-100.
Description
Not required
Supplementary information about the DNAT rule. Enter up to 255 characters. Angle brackets (<>) are not allowed.
- Click OK.
After you add a DNAT rule, add rules to the security group associated with the servers to allow inbound or outbound traffic. Otherwise, the DNAT rule does not take effect. For details, see .
Step 5: Verify that the DNAT Rule Has Been Added
- In the DNAT Rules tab, view details of the DNAT rule and check whether the DNAT rule has been created.
If Status of the SNAT rule is Running, the SNAT rule has been created.
Step 6: Verify that Servers in a VPC Can Be Accessed from the Internet Through the NAT Gateway
- Log in to ECS 02 with an EIP bound.
- On ECS 02, ping the EIP (120.46.131.153) to check whether ECS 01 on the private network can be accessed by ECS 02 on the public network through the NAT gateway.
Figure 2 Verification result
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