If there are two or more private IPs configured to your account, you can create Private IP Pools. This allows even more control of delivery of email over certain IP addresses.

Go to the Private IP tab in your Account Settings.
Click on "Manage IPs", then click on "Create IP Pool".

Give the IP Pool a name and a description. Save it, then go back to the settings where you can assign the IPs to the IP Pool that has just been created.

In the campaign creator there will now be an option to select which Private IP Pool to be used for the campaign. The email will send exclusively from the IPs in the selected IP Pool.

On your Subaccount Management screen you can now assign IP Pools to sub accounts. And the email for that sub account will send exclusively on the IPs in the assigned IP Pool.

To use a specific Private IP Pool when sending via API, just include the 'poolName' parameter in your email/send call:

https://elasticemail.com/developers/api-documentation/rest-api#operation/emailsPost

http://api.elasticemail.com/public/help#Email_Send

HTTP API query string snippet Example: &poolName=PoolA

To use a specific Private IP Pool when sending via the SMTP, just include the 'poolName' header. Make sure Custom Headers is enabled in your Account Sending Settings.

SMTP Example: poolName: PoolA