On the menu bar, go to Tools > Global Options.
Click Transfer.
Choose Auto-detect to have CuteFTP decide the transfer method based on the file and server type.
Choose ASCII to transfer text files, web pages or other text type files.
Choose Binary to transfer pictures, programs or executable files.
Note Binary files cannot be transferred in ASCII mode, but ASCII files can be transferred in Binary mode.
Data mode:
Choose Auto and CuteFTP will try to make connections in PASV mode. If the PASV connection fails, CuteFTP will try the connection in PORT mode automatically.
PASV helps avoid conflicts with security systems. PASV support is necessary for some firewalls and routers, because with PASV, the client opens the connection to an IP Address and port that the server supplies.
ChoosePORT when connections or transfer attempts fail in PASV mode, or when you receive data socket errors. When an FTP client connects using PORT, the server opens a connection to an IP Address and port that the client supplies.
Note
If you connect in PORT mode your session becomes vulnerable to "Port theft", where a third party can interfere with transfers.
Use this to define a port range when establishing connections via port mode.
Use local port range when you have a defined limited number of open ports on your firewall.
Select this to transfer files on servers when you are only allowed one connection to the server or the server is slow to respond to login requests.
Clear this option if your server allows multiple connections and is quick to respond and you want to navigate the site while downloading.
Note
When selected, CuteFTP will use the browse session and if available, additional connections as well. For example, If you define a per site max limit of 5 connections and transfer 5 files, CuteFTP will check the browse connection first to see if it is busy, and if not busy, will transfer the 1st file over the browse connection. The subsequent 4 files will be transferred over 4 additional sessions. CuteFTP will automatically make adjustments for allowed connections (both from client and server perspectives) and whether or not it can use the browse session.
When cleared, you basically force all transfers over new connections, freeing up the browse session so you can continue to navigate. The only time this poses a problem is when the server either refuses to allow multiple connections or is slow to log into.
When selecting MAX in a multi-part transfer, use n threads (CuteFTP Professional only)
Select the number of parts to split a file when a max multi-part transfer is requested.
Select the time that CuteFTP Professional will wait to try again after an interrupted or failed download. Select a time between 0 and 1,000 seconds (about 17 minutes).
Roll back (retry at byte offset) n bytes when resuming transfers
Select the number of bytes prior to the transfer failure CuteFTP will resend when attempting to finish an interrupted transfer. Select between 0 and 65536 bytes.
Send REST command prior to APPE when resuming a transfer
Select this check box to send the REST (Restart) command to resume a transfer, before sending the APPE (Append) command.
Clear this check box to send the APPE (Append) command to resume a transfer without first sending the REST (Restart) command.
Tip
Most of these controls are intended for advanced users only. For example, the REST/APPE sequence is only intended for problem servers that don't support the proper resume sequence. Transfer type should only be changed when you need to force files to transfer a certain way. The data port mode should only be changed if you are having problems establishing a data connection (on LIST or RETR for example). Limiting the local port range can have adverse affects when transferring many small files over a narrow range of ports.