For file transfer protocol (FTP) communication, clients open a TCP-based control channel on port 21. For active FTP, a second data channel is initiated from the server to the client via port 21. NSX Advanced Load Balancer only supports passive FTP, in which the client initiates the data channel via a high port negotiated with the server.
A Note on High Availability
Exactly one SE in an SE group may deliver the FTP service at any given time. Virtual service scale-out to two or more SEs is not supported with NSX Advanced Load Balancer FTP. Therefore, legacy active/standby and 1+M elastic HA are supported. Active/active elastic HA is not.
Virtual Service Settings:
Application Profile: L4
TCP/UDP Profile: TCP-proxy
Service Ports: Set to Advanced via the NSX Advanced Load Balancer UI
Port: 21 to 21
Port: 1024 to 65534
Load Balance Algorithm: Least Connections
Persistence: Client IP
Health Monitor: TCP
Health Monitor Port: 21
Port Translation: Disable
Active FTP is not supported. NSX Advanced Load Balancer recommends the use of passive FTP as a workaround.
> ftp ftp.test.com Connected to ftp.test.com. ftp.test.com FTP server ready. Name (test:user): anonymous Password required for anonymous. Password: ****** User anonymous logged in. Remote system type is UNIX. Using binary mode to transfer files. ftp> passive Passive mode on.