USER-PASS-ACCT Authentication Command Sequence
The FTP Client uses the following command sequence to make a connection when you have configured Style to USER-PASS-ACCT in the Firewall section of the Security Properties dialog box.
OPEN <FTP_server>
USER <FTP_server_username> <firewall_username>
PASS <FTP_server_password>
ACCT <firewall_password>
More information