I don't use FTP.
After upgrade the latest firmware, did you reset and reoconfigure it?
Check your settings step by step. http://www.tp-link.com/en/article/?faqid=341

Yes. Before upgrade, restore factory reset. After upgrade, reset, and reconfigure. All settings same as before.
Anyone, your FTP is still OK or NOT?

soma wrote

Yes. Before upgrade, restore factory reset. After upgrade, reset, and reconfigure. All settings same as before.
Anyone, your FTP is still OK or NOT?

Your ftp server is a HDD or server ?
if it is a server you may try doing a port forwarding for your server.

I use a pin drive on the usb port of the router WDR4300. It worked before.
I did use a port forwarding (since yesterday) doesn't seem to make it work. Is it a correct setting? see pic->

I don't think your setting is correct. Go to USB Settings---FTP Server to check FTP server configuration as the instruction given by Mavis.
By the way, your USB driver can still be detected, right?

Dear Ada,
The setting of FTP server is the same as before upgrade. see the pic.



The difference is, before, I can detect the port 21 open on the internet, outside LAN, and access FTP; after upgrade, I can NOT detect port 21 open on the internet, outside LAN, no access FTP.
More stangely I now can access the FTP within my LAN, with the internet IP address or my Dyn DNS. Before upgrade it is not possible. (If I remembered correctly).

Is it only my problem or a bug of the firmware?

Ada if you run a ftp with the USB on the WDR4300 (140916), can you please confirm your FTP is still OK or NOT?

My router is OK, I think you need test more times. You can see the help on the firmware.The internet address is used for the remote access.( ftp://WAN IP)
But if you are in the LAN , you need use ftp://192.168.0.1 to access it.

stangang wrote

My router is OK, I think you need test more times. You can see the help on the firmware.The internet address is used for the remote access.( ftp://WAN IP)
But if you are in the LAN , you need use ftp://192.168.0.1 to access it.

The strange thing is that in the LAN I can access the FTP either use local address or wan-IP address, even my DYN DNS. But outside my LAN, no access.