Only devices that at least once were in the network of our enterprise can enter via FTP, what is the reason for this and how to solve it?

Question

Computer networks

By ftp comes only from devices that were once in the network of our organization, how to give access to other devices?

Answer 1

Most likely, on those devices that were once in LAN, someone simply activated the "passive FTP" checkbox in the explorer settings. Well, the server only works with it, because of the NAT settings curve.

Answer 2

write a rule on the firewall?
first, make sure what the problem is: check the availability of the port, check the authentication method on ftp.