Android Question FTP.Upload not working on 4G

[johnnyv]

I have an app that uploads a file to an FTP server every few minutes. It works great when my phone is on a WIFI connection. However, if I turn Wifi off and it is using the 4G or 3G connection, the upload doesn't work.

Here are the symptoms when using 4G or 3G connection:

1. I have a 9 kb file on the phone that I am uploading to the FTP server.
2. Upload initiates, but the FTP_UploadProgress and FTP_UploadCompleted events are never triggered.
3. On the FTP server, I see that it created a file with the correct filename, but it is an empty file.

I have tried both active and passive FTP modes (not that I really understand the difference). Neither worked.

Is there some kind of issue with FTP over a 4G or 3G connection?

 

[lemonisdead]

Hello,

By my experience : some providers block the major servers ports and allow port 80 only.
My solution was to upload using a php form and not the ftp.

 

[johnnyv]

Thanks! SMTP seemed to work on both, so I used that.

 

[jefflynn1974]

I have exactly the same problem too! Plus I found this under WiFi connection as well. Is there any solution? This is very troublesome.

 

[Erel]

Have you tried setting passive mode to true?

 

[jefflynn1974]

Yes, but there was no change.

 

[Erel]

It means that your mobile network provider blocks the relevant port.

If it doesn't work with wifi then there is a different problem. Might be a firewall issue.

 

[jefflynn1974]

I think the problem would be something else because I've tried with an another FTP client app from the Play store and it worked perfect with WiFi and mobile connection too. Only my B4A app can't add file to the server.

 

[Erel]

Can you post your code?

 

[jefflynn1974]

I checked again and it seems the WiFi was really a network problem. Sorry.
Today I tried also with mobile connection and I don't know why and how but it worked good too. Maybe there was a trouble at my mobile network provider's system.

 

[tigrot]

Sometimes I think that those are network problems. Some subnetworks could be inaccesible at certain times... you wait for some time and they are pingable again.