this is strange. Are you able to provide a packet capture that shows the traffic?
I think that FILEZILLA try to download big file by part which can be restricted.
Please look at aour MWG access log files - this is the first step to resolve issue.
Per standard MWG prevents partial downloads, as they are evil to security.
Do you have datatrickling enabled?
How are the users connecting to MWG with Filezilla?
CONNECT or localuser@locasite@remoteuser@remotesite?
Yes, Data trickling is enabled.
Additionally, as suggested by vendor, connection settings are made as, Connection --> FTP --> FTP Proxy-> Site
Proxy Host: <proxy IP>:2121
Proxy Username/Password: set as Domain credentials.
Above are set in the FileZilla.
Surprisingly, we have TWO appliances with different versions with identical settings.
Issue is faced with MWG 6.8.7 build 8846 while when checked with MWG 6.8.7 build 837 FTP transfer is working fine.
Andre, can you guide me the tcpdump with TCPDUMP caommand that can be helpful in this case, as I checked the dumps there is no error seen when TIMEOUT occurs.
Appreciating your support..