Adds a Source Network Address Translation (SNAT) entry to an SNAT table.

Descriptions

When you call this operation, take note of the following items:

  • CreateSnatEntry is an asynchronous operation. After you make a request, an SNAT entry ID is returned but the specified SNAT entry is not added. The system adds the entry in the background. You can call the DescribeSnatTableEntries operation to query the status of the SNAT entry.
    • When the SNAT entry is in the Pending state, the system is adding the SNAT entry. You can only query the status of the SNAT entry, and cannot perform other operations.
    • When the SNAT entry is in the Available state, the SNAT entry is added.
  • The vSwitch and Elastic Compute Service (ECS) instance specified in the SNAT entry must be created in the virtual private cloud (VPC) where the NAT gateway is deployed.
  • Each vSwitch or ECS instance can be specified in only one SNAT entry.
  • If a high-availability virtual IP address (HAVIP) exists in the vSwitch, you cannot create SNAT entries.

Debugging

OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer. OpenAPI Explorer dynamically generates the sample code of the operation for different SDKs.

Request parameters

Parameter Type Required Example Description
Action String Yes CreateSnatEntry

The operation that you want to perform. Set the value to CreateSnatEntry.

RegionId String Yes cn-hangzhou

The ID of the region where the NAT gateway is deployed. You can call the DescribeRegions operation to query the most recent region list.

SnatIp String Yes 47.98.XX.XX

Separate multiple elastic IP addresses (EIPs) in the SNAT entry with commas (,).

Note If you select multiple EIPs to create an SNAT address pool, connections are hashed to these EIPs. Network traffic may not be evenly distributed to the EIPs because the amount of traffic passes through each connection varies. We recommend that you associate these EIPs with the same EIP bandwidth plan to prevent service interruptions due to the bandwidth limit of an individual EIP.
SnatTableId String Yes stb-bp190wu8io1vgev****

The ID of the SNAT table.

SourceVSwitchId String No vsw-bp1nhx2s9ui5o****

The ID of the vSwitch that requires Internet access.

SourceCIDR String No 10.1.1.0/24

You can specify the CIDR block of a VPC, a vSwitch, or an ECS instance or enter a custom CIDR block.

  • You can specify the CIDR block of the VPC where the NAT gateway is deployed. Then, all ECS instances in the VPC can access the Internet through SNAT.
  • You can specify the CIDR block of a vSwitch. Example: 192.168.1.0/24. When the ECS instances that belong to the vSwitch send requests to the Internet, the NAT gateway provides SNAT services.
  • You can also specify the IP address of an ECS instance. Example: 192.168.1.1/32. When the ECS instance sends requests to the Internet, the NAT gateway provides SNAT services.
  • You can enter a custom CIDR block. Then, all ECS instances within the specified CIDR block can access the Internet through SNAT.

If SnatIp is set to one public IP address, the ECS instance uses the public IP address to access the Internet.

If SnatIp is set to multiple public IP addresses, the ECS instance randomly selects an IP address specified in the SnatIp parameter to access the Internet.

This parameter and the SourceVSwtichId parameter are mutually exclusive. If the SourceVSwitchId parameter is specified, you cannot set the SourceCIDR parameter in the same request. If the SourceCIDR parameter is specified, you cannot set the SourceVSwitchId parameter in the same request.

SnatEntryName String No SnatEntry-1

The name of the SNAT entry.

The name must be 2 to 128 characters in length. It must start with a letter or Chinese character but cannot start with http:// or https://.

ClientToken String No 02fb3da4-130e-11e9-8e44****

The client token that is used to ensure the idempotence of the request. You can use the client to generate the value, but you must make sure that it is unique among different requests. The ClientToken can contain only ASCII characters. It cannot exceed 64 characters in length.

Response parameters

Parameter Type Example Description
SnatEntryId String snat-kmd6nv8fy****

The ID of the SNAT entry.

RequestId String 2315DEB7-5E92-423A-91F7-4C1EC9AD97C3

The ID of the request.

Examples

Sample requests

http(s)://[Endpoint]/?Action=CreateSnatEntry
&RegionId=cn-hangzhou
&SnatIp=47.XX.XX.98
&SnatTableId=stb-bp190wu8io1vgev****
&<Common request parameters>

Sample success responses

XML format 

<CreateSnatEntryResponse>
      <RequestId>2315DEB7-5E92-423A-91F7-4C1EC9AD97C3</RequestId>
      <SnatEntryId>snat-119smw5tkx****</SnatEntryId>
</CreateSnatEntryResponse>

JSON format 

{
    "SnatEntryId": "snat-kmd6nv8fyx****",
    "RequestId": "2315DEB7-5E92-423A-91F7-4C1EC9AD97C3"
}

Error codes

HttpCode Error code Error message Description
400 Forbidden.SourceVSwitchId.IncludeHaVip There is some HaVips under specified VSwitch The error message returned because one or more HAVIPs belong to the specified vSwitch.
400 InvalidSnatIp.Malformed The specified SnatIp is not a valid IP address. The error message returned because the specified public IP address is invalid.
400 SNAT_IP_POOL_COUNT_TOO_MANY The Snat pool ip too many. The error message returned because the number of IP addresses in the SNAT IP address pool reaches the quota.
400 Forbidden.SnatEntryCountLimited SNAT entry in the specified SNAT table reach it?s limit. The error message returned because the number of SNAT entries reaches the quota.
400 NOT_ALLOW_USE_SOURCECIDR The User not in nat_scope_unlimited white list. Cannot use SourceCidr param. The error message returned because the specified private IP address is not within the CIDR block of the VPC.
400 INVALID_PARAMETER The parameter invalid. The error message returned because the specified parameter is invalid.
400 Forbidden.SourceVSwitchId.Duplicated The specified SourceCIDRis duplicated. The error message returned because a SNAT entry is already created for the specified vSwitch.
400 Forbidden.IpUsedInForwardTable The specified SnatIp already used in forward table The error message returned because the specified public IP address is already used by a DNAT entry. Select another public IP address or delete the DNAT rule that uses the specified public IP address.
400 Forbindden The specified Instance already bind eip The error message returned because the ECS instance is associated with an EIP. Disassociate the EIP from the ECS instance before you create forwarding rules.
400 OperationUnsupported.CidrConflict The specified CIDR block conflicts with an existing SNAT entry. The error message returned because the specified CIDR block conflicts with those in existing SNAT entries.
400 InvalidParameter.Name.Malformed The specified Name is not valid. The error message returned because the specified name is invalid.
404 InvalidRegionId.NotFound The specified RegionId does not exist in our records. The error message returned because the specified region ID does not exist.
404 InvalidSnatTableId.NotFound Specified SNAT table does not exist. The error message returned because the specified SNAT table does not exist. Check whether the ID of the SNAT table is valid.
404 InvalidVSwitchId.NotFound The specified virtual switch does not exists. The error message returned because the specified vSwitch does not exist. Check whether the specified ID is valid.
404 InvalidSnatIp.NotFound Specified SnatIp does not found on the NAT Gateway The error message returned because the specified public IP address is not found on the NAT gateway.

For a list of error codes, visit the API Error Center.