There is a problem with connecting to the Guardian OS based Snap using FTPS/FTPES - FTP over explicit TLS/SSL. This has been replicated on Snaps on 5.1.046, 5.2.056 and 5.2.056 SP1 using Filezilla 18.104.22.168. Seen on Snap 110, 210, 620. This appears to be a problem with FIlezilla 3.1.0 and above per http://bugs.proftpd.org/show_bug.cgi?id=3094
We have verified that the following clients function at this time:
Core FTP lite
This issue will be addressed in a future release of Guardian OS.