Filename Convert
Sets filename case conversion during transfer for uploading/downloading/FXPing
Unchanged: keep original filename case.
ALL UPPERCASE: converts all letters to uppercase
all lowercase: converts all letters to lowercase
First letter uppercase: converts first letter to uppercase

XDupe is a FTP server feature,
Enable XDupe: if checked, FTPRush will use XDupe option during transfer
Refresh directory when XDupe do not return result: if checked and XDupe option enabled, FTPRush will try to refresh FTP directory and do comparision again to skipping files faster when XDupe do not return the file dupe list.

FXP method
The normal FXP order is: source FTP PASV, target FTP PORT, but not all sites follow this implement.
Do not use PASV when acts as source FXP FTP: if checked, FTPRush will let target FTP server executing PASV command. it be used when source FTP does not support PASV command.
Use PASV when acts as target FXP FTP: if checked. FTPRush will let destination FTP Server executing PASV command. it be used when target FTP does not support PORT command from foreign IP address.

Uploading and Downloading
Force Active Mode Transfer
Use Global Settings: gets settings from Global option.
Yes: enable transferring with Active Mode (PORT)
No: disable transferring with Active Mode (PORT)

TCP/IP Buffer Size
Sets TCP/IP buffer size. Up to 1M bytes. Warning: This is a advanced feature, except you know what you doing, otherwise keep it as default 8k size