To transfer files to your company's internal network from home, you use FTP$.$ The administrator has recently implemented a firewall at the network perimeter and disabled as many ports as possible.

Now, you can no longer make the FTP connection. You suspect the firewall is causing the issue.

Which ports need to remain open so you can still transfer the files? $($Select two.$)$

answer

$23$

$80$

$21$

$443$

$20$