Synology NAS

FTP passive mode

plesk-12-backup-personal-ftp-repository-error
Finally, after some tcpdumps, I found the reason why I could list files, but plesk couldn't connect.

When you see traces, plesk connects to FTP, but make some tests to check all is OK. One of this checks is to send a SYN packet to the Passive Port given by FTP in Entering Passive Mode packet. When you list files with curl, you donÂ´t test if you can reach to passive port. You enter in passive mode, but you just send the list command to port 21. You don't use passive port.

But now the tricky. It happens with some FTP servers, like mine, that are not clever: you configure default passive ports (55536-55539), but then in Entering Passive Mode packet, offers a port outside this range, normally a port like 550XX (55002, 55003, 55004,…).

So the solution was simple: set passive port range from 55000-55539 (and in my case, nat in router from 55000-55539 to my ftp server, and port 20-21, obviously).

IP

Zie Keepass voor info

Login

via ssh, zie Keepass
via browser https://ipadress:5001 of https://dnsnaam:5001

Command line

Synolog CLI commands