Sell provides a fixed range of outgoing IP addresses that you can whitelist, helping you to increase the security of your email integration. Every email that a user sends from Sell is sent from our official IP range of 188.8.131.52/25.
This is a range of 128 different IP addresses, starting from 184.108.40.206 through to 220.127.116.11.
All of these IP addresses should be whitelisted to ensure that your Sell email integration works properly.
You'll need to contact your email service provider or support team, and your security team if you have a firewall, to whitelist these IP addresses, as this can't be set in your Sell account.
See Configuring your firewall for use with Zendesk for more information on Zendesk firewall recommendations.