SFTP Backups with Serv-U FTP

[Ron Lyen]

Using Serv-U FTP as the destination for our 3CX backups, we have set our Windows based 3CX servers to backup to it. It backs up there and when we delete a backup in 3CX, it removes it from the Serv-U FTP folders. All fine and dandy so far. Now we use WinZip to open and view the zipped backup files on Serv-U FTP folders and it does not open and show all the folders and files like a local back up does. We get the "Error: central directory not found" and then "Cannot open file xxx.zip. It does not appear to be a valid archive". The zip file size is exactly correct as we compare it to local backups that do open fine. We are running Enterprise 16.0.8.9 on Server 2019 1809.

 

[ChrisC_3CX]

As a first note, do bear in mind that the FTP servers tested with 3CX are FileZilla FTP and Synology FTP, that of course is not to say that other FTP servers will not work but there may be additional settings you might need to modify.

When do you get the error, when you try to open the file from the FTP server itself or do you first download it? Try downloading it from the 3CX Management Console and then try opening it again, do you still get the same issue? If yes, also give another archiving tool a try such as 7zip, WinRar, etc, is it still the same?

 

[Ron Lyen]

We have opened the 3CXScheduledBackup.1.zip file that 3CX generates from both the FTP server directory and by copying to a local drive on my pc. Tried opening with Windows Explorer, full version of newer Winzip and 7-zip. When we do a normal local backup on the 3CX server, we can open with any of them apps.

 

[ChrisC_3CX]

When you say that you copied the backup to your PC, do you mean you downloaded it from the 3CX Management Console or directly from the FTP server? If directly from the FTP server, try downloading it from the Management Console as well, do you get the same thing?

Also, you mention a scheduled backup, does the same issue occur even when performing manual backups? Manually create a backup, download it from the Management Console and check to see if there is any difference.

 

[Ron Lyen]

Backup file opens fine with Manual backup and Backup to Local drive of 3CX servers. Only a problem with the backup file when run with a SFTP backup.

I have full access to the FTP servers, so when i say copied, I literally copied \\ftpserver\FTPfolders\3CXbackup.zip to my local desktop just to test if i could open it with better luck. No better result though.

 

[NickD_3CX]

I'm not sure how a local Backup ZIP file and the one that is uploaded to the FTP can be the same size, but the one opens normally and the other does not.
I would also recommend maybe doing an MD5 comparison of the 2 files because there must be a difference.

To the point though, it must be some setting of the FTP Server, or something happening during the transportation of the file there.

Do you have one of the tested FTP servers setup somewhere where you can check your 3CX against one of those? If it works on another one, at least then you can focus your attention on the FTP software.