If I am on my LAN I can connect problem free using the IP of my server. If I am outside (and this just started happening today) of my LAN and I try to connect to my server, this is the error I get:

Status: Resolving address of XXXX.XXXX.org
Status: Connecting to XX.XX.XXX.168
Status: Connected, performing TLS handshake...
Status: TLS handshake successful, verifying certificate...
Status: Waiting for welcome message...
Reply: 220-FileZilla Server 0.9.53 beta
Reply: 220-written by Tim Kosse (tim.kosse@filezilla-project.org)
Reply: 220 Please visit http://sourceforge.net/projects/filezilla/
Command: CLNT https://ftptest.net on behalf of XX.XX.X.131
Reply: 200 Don't care
Reply: 331 Password required for XXXXX
Command: PASS ******
Reply: 230 Logged on
Command: SYST
Reply: 215 UNIX emulated by FileZilla
Command: FEAT
Reply: 211-Features:
Reply: MDTM
Reply: SIZE
Reply: MLST type*;size*;modify*;
Reply: MLSD
Reply: PROT
Reply: PBSZ
Reply: UTF8
Reply: CLNT
Reply: MFMT
Reply: EPSV
Reply: EPRT
Reply: 211 End
Command: PBSZ 0
Reply: 200 PBSZ=0
Command: PROT P
Reply: 200 Protection level set to P
Command: PWD
Reply: 257 "/" is current directory.
Status: Current path is /
Command: TYPE I
Reply: 200 Type set to I
Command: PASV
Reply: 227 Entering Passive Mode (XX,XX,XX,XXX,166,216)
Command: MLSD
Reply: 425 Can't open data connection for transfer of "/"
Error: Listing failed

What do I do to resolve this? I am running FileZilla Server that I am trying to connect to. The user I am logging in as has valid credentials and am connecting on the appropriate port. I am using FileZilla Client version 3.8.0 to try and connect.


1 Answer 1


Command: PASV
Reply: 227 Entering Passive Mode (XX,XX,XX,XXX,166,216)
Command: MLSD
Reply: 425 Can't open data connection for transfer of "/"

The data connection port on your FTP server is not accessible.

The port number for this specific connection was 42712 (=166*256+216). But in general, there's a port range. So that whole port range needs to be made accessible.

enter image description here

Check all firewalls (both internal on the FTP server machine and external) and NATs on the way between your client and the server. They all need to allow and correctly route the connections to the ports in the data connection port range.

For details, see

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