If you, your supplier, or your 3PL need to whitelist Duoplane's IP address for an FTP connection you will need to ensure all of the below IP addresses are whitelisted. What this will do is allow Duoplane to access your vendor's FTP to either deliver or retrieve files such as purchase orders, inventory feeds, or shipping feeds.
45.56.65.204
45.79.8.48
45.79.17.67
50.116.23.48
173.255.202.177
173.255.201.212
For further questions you can contact our support team at support@duoplane.com.