External FTP client connetion in the clond not passing though a TZ400 Sonic Wall to a server behind

MIS_ShopperWorld

We have a TZ400 Sonic Wall at all of our remote retail locations. There is a AS400 in the cloud that connects to all Point of Sales servers at the retail locations and downloads the price updates and markdowns. FTP is used as the mode of communications to transfer the data down from the cloud and the servers on the store level. FTP from the cloud down to the servers was working about (2) weeks ago. This week, we are unable to use FTP for this data transfer. We haven't made any changes on the TZ400 sonic wall. Below is the model number and firmware ver on the sonic wall:

1) Model: TZ 400

2) Firmware Version:SonicOS Enhanced 6.5.4.7-83

3) Product Code: 12431

I have (2) questions:

1) How do I use the Sonic Wall logs to see what error message are being generated and why the FTP session is denied.

2) How can I confirmed the FTP ports and protocols are enable?

TKWITS

1: The logs on the Sonicwall will not provide this information. You'd have to look at the FTP server for that. You might be able to scub some info along those lines from a packet capture though.

https://www.sonicwall.com/support/knowledge-base/how-can-i-setup-and-utilize-the-packet-monitor-feature-for-troubleshooting/170513143911627/

2: Let me google that for you...

https://www.sonicwall.com/support/knowledge-base/configuration-for-a-passive-mode-ftp-server-behind-the-sonicwall/170505318942162/

https://www.sonicwall.com/support/knowledge-base/sonicwall-configuration-for-active-mode-ftp-client-connections-with-client-behind-the-sonicwall/170503414367365/

Saravanan

Hi @MIS_SHOPPERWORLD,

Thank you for visiting SonicWall Community.

The best way to determine if the firewall disregards the FTP packets is to perform a packet monitor. Along with packet monitor you could also make sure the Log Category Network and its sub category Network Access is enabled to see some logs on the SonicWall if any port forwarding violations occur.

Without any changes being done on the SonicWall, the FTP function shouldn't have broken. Were there any FTP client upgrade or FTP server underwent any changes? Since you are trying to initiate the FTP connection from remote locations to behind SonicWall, did you already had the port forwarding configured on the firewall?