C7000 - Performing FTP but retrieved data being blocked coming back

[rstambau]

Hello.  I have an AC1900/C7000 Netgear Wifi Router.  I am running an application that performs an FTP to an external server and retrieves data back. For some reason the data is being blocked from being retrieved with the router/modem.  I tried it on my PC using an iPhone hot spot and it worked fine. 

Anybody know why the data is being blocked and is there a way to whitelist the IP for the server I am trying to FTP so it allows the data to be retrieved?  My firmware version is V1.01.15. Thank you.

[antinode]

> [...] I am running an application that performs an FTP to an external
> server and retrieves data back. [...]

   The FTP server is somewhere in the outside world, not on your LAN?

> [...] For some reason the data is being blocked from being retrieved
> with the router/modem. [...]

   It's not obvious (to me) that your modem+router is the cause of that
behavior.

> [...] I tried it on my PC using an iPhone hot spot and it worked fine.

   That's the same computer, doing exactly the same (unspecified) task,
just using a different network connection?

> Anybody know why the data is being blocked [...]

   Not I.  Can you use some simple/reliable FTP client program to
communicate with this (unspecified) FTP server (not using your
(unspecified) "an application")?  Do you have any trouble with any other
FTP server (or client program)?

   Without know what you and your "an application" are actually doing,
and what the actual failure is, it would be tough to do more than guess
what the actual problem might be.  "Doesn't work" is not a useful
problem description.

   Firmware on a C7000 is out of your control, so, about the only
router-related action which you could take might be a settings reset,
and manual reconfiguration.

[rstambau]

FTP to external server outside our LAN

Yes the app retrieved data using iPhone hotspot on the same PC

Used Filezilla and couldn't retrieve data with router/modem, but did work when using iPhone hotspot

Thanks for your reply.  We will keep troubleshooting.  Very strange.  Nobody else(outside our WiFi network) using the app is experiencing this.

[antinode]

> Used Filezilla and couldn't retrieve data with router/modem, [...]

   Again, "couldn't" is not a useful problem description.  It does not
say what you did.  It does not say what happened when you did it.  As
usual, showing actual actions with their actual results (error messages,
LED indicators, ...) can be more helpful than vague descriptions or
interpretations.

   Are you using passive-mode FTP?  Filezilla does/can log all session
activity, right?  What actually happens in one of these failures?

> [...] Nobody else(outside our WiFi network) using the app is
> experiencing this.

   Does a wired connection work any differently?  Is there any
port forwarding configured on the C7000 (which might affect ports
20-21)?  (A settings reset should clear out anything like that.)