FTP transfer from specific region stop working since FG-90d deployed

[KelvZeng]

This is a very weird situation and I hope I can get some help here.

Since I deployed a FG-90d firewall device in my office in New Zealand, a FTP client PC in USA is no longer able to upload large files to our FTP server in NZ. All other clients in NZ and AUS are working fine as usual as tested.

The PC in USA which has issue can establish connection with the server, it can also tranfer samll files. But when I try to upload large file (600m) it will fail at 4% or something like that. Error message '502 Command REST not allowed by policy'.

Before the FG-90d was deployed it worked fine.

I have reviewed all settings on the firewall device and found nothing blocking this.

Any advice will be greatly appriated.

[FortiMinh]

The firewall's FTP session helper might be blocking the REST command needed to re-initiate the FTP transfer at any given point (which is more likely since you are doing large file transfers)

Did you try enabling the FTP and sub protocols (such as FTP-PUT) in your security policy? I would also disable the FTP session helper altogether to see if it helps.

Minh-Quang Nguyen, CISSP
Systems Engineering | Eastern Canada