Ftp: 425 Unable to build data connection

Error Message:

LIST
425 Unable to build data connection: Connection timed out
PASV
227 Entering Passive Mode (xx,xx,xx,xx,xx,xxx).
connecting data channel to xx.xxx.xx.xxx:54963

The above error message is received while you Ftp to an account successfully but it does not list the files and directories within it. The reason for the error message is, the kernel modules that are required for Ftp “i.e. to keep track of every Ftp connection and carry out the data transfer of it on another port” is not loaded.

The modules are “ip_conntrack” and “ip_conntrack_ftp” which has to be loaded using the ‘modprobe’ command. Login to your server as user root and execute the following commands:

/sbin/modprobe ip_conntrack
/sbin/modprobe ip_conntrack_ftp

Once done, restart the ftp service and re-connect to your account via Ftp. This time it will list the files and directories.