Android Question Unable to connect my FTP server on Vodafone network!

[tigrot]

Hi Everybody,
I have this strange issue: I have an APP comunicating via FTPS to my webserver. Everything is ok if I play with transfer via cabled network(XDSL), if I connect via Vodafone UMTS(or LTE) network the AUTH command seems to be the last thing received by IIS FTP server. Tested from another FTP APP the issue seems the same on the same network.
I must remember i use Explicit FTP over TLS.
The command source is :

  FTP.Initialize("FTP","www.xxxxxx.it",21,"YYYYYY","ZZZZZZZZZZZ")
  FTP.PassiveMode=True
  FTP.UseSSL=False
  FTP.SetCustomSSLTrustManager(managerx)
  FTP.UseSSLExplicit=True

Does anybody know the solution?

Best regards
Mauro Zanin

 

[giga]

Do you have an error generated or is it just slow?

 

[tigrot]

No it seems to do anything(the sequence of events seems to break). On server's log there is only CONNECT- AUTH - DISCONNECT
I've read about this issue, but never had the chance to see...

Ciao
Mauro

 

[giga]

Just a thought. Do you think this could be a timeout issue or a provider port restriction problem?

 

[tigrot]

Hi Giga,
for sure I have traced the issue. I get connection, send AUTH message, then the server waits indefinitelly for TSL handshake. I have tested many clients and I get the same. Maybe there is a filter on this port. The strange is that AUTH message passes! I'm trying to implement SFTP but B4A implementation is very poor. At present I'm unable to use it, the server states "Unknown protocol". I've tested the SFTP server using some commercial clients and it works very well.
Since I love to write original protocols. I'll create one just for added security.
Thank you to care about my problems! And have a nice week...
Mauro

 

[giga]

Your Welcome.

 

[tigrot]

Just to explain the issue: I had to disable Kerberos protocols on server, so I was able to transfer. Thanks again!