Error message of SocketTimeoutException when SFTP tries to connect

[TMJ]

SFTP set up but connection can only be good like several hours before FTP/SFTP client shows the error message of "Software caused connection abort java.net.SocketException: Software caused connection_abort". (Another FTP/SFTP client's error message is Session.connect: java.net.SocketTimeoutException: Read timed out).

The SFTP can work for a little while, sometimes as short as a couple of hours, before the same thing happens. The NSA is F2-210 and TOS is 4.2.43.

Any idea what the fix can be? Thank you very much.

[TMzethar]

Will there be errors when you use other software to connect? For example, winscp. In addition, the port of SFTP is 9333.

[TMzethar]

Based on your feedback from other channels, we understand that you are using the SFTP tool on your Android phone to connect via the Internet IP+mapped port.
Judging from your description of the abnormal situation after a few hours of use, it is guessed that the allocated Internet IP may have changed automatically.
It is recommended that you use DDNS instead of IP. For the method of setting DDNS, you can refer to this:
viewtopic.php?f=78&t=433

[TMJ]

Will there be errors when you use other software to connect? For example, winscp. In addition, the port of SFTP is 9333.

Does it have to be 9333? (As I described, SFTP can work for a while when port set to be 21). I set port 21 for SFTP and make port 22 open at my windows firewall and my ISP router IPV4 forward.

[TMJ]

Based on your feedback from other channels, we understand that you are using the SFTP tool on your Android phone to connect via the Internet IP+mapped port.
Judging from your description of the abnormal situation after a few hours of use, it is guessed that the allocated Internet IP may have changed automatically.
It is recommended that you use DDNS instead of IP. For the method of setting DDNS, you can refer to this:
viewtopic.php?f=78&t=433

Thank you for your reply. I tried a DDNS address. Again, same thing, SFTP had successfully worked a while (whether I used IP address or DDNS address) before I got the error message.

[TMJ]

Based on your feedback from other channels, we understand that you are using the SFTP tool on your Android phone to connect via the Internet IP+mapped port.
Judging from your description of the abnormal situation after a few hours of use, it is guessed that the allocated Internet IP may have changed automatically.
It is recommended that you use DDNS instead of IP. For the method of setting DDNS, you can refer to this:
viewtopic.php?f=78&t=433

Thank you for your reply. I tried a DDNS address. Again, same thing, SFTP had successfully worked a while (whether I used IP address or DDNS address) before I got the error message.

Also forgot to mention, my internet IP address stayed the same when SFTP worked then became unavailable due to timeout.

[TMzethar]

As long as it does not conflict with the ports of other services
But the default port for FTP is also 21, you should have already modified it, right?

We suspect that there may be processes occupying network or system resources, which may affect SFTP
Please try connecting to SFTP within the local area network first to investigate if it is your network issue

[TMJ]

As long as it does not conflict with the ports of other services
But the default port for FTP is also 21, you should have already modified it, right?

We suspect that there may be processes occupying network or system resources, which may affect SFTP
Please try connecting to SFTP within the local area network first to investigate if it is your network issue

How can I see what process is occupying the network? I looked at system log, nothing but my connected was recorded.

Since you guys are in favor of FileZilla, I installed FileZilla on my windows laptop. The error message I got is
"Error: Connection timed out after 20 seconds of inactivity
Error: Could not connect to server"

[TMJ]

As long as it does not conflict with the ports of other services
But the default port for FTP is also 21, you should have already modified it, right?

We suspect that there may be processes occupying network or system resources, which may affect SFTP
Please try connecting to SFTP within the local area network first to investigate if it is your network issue

How can I see what process is occupying the network? I looked at system log, nothing but my connected was recorded.

Since you guys are in favor of FileZilla, I installed FileZilla on my windows laptop. The error message I got is
"Error: Connection timed out after 20 seconds of inactivity
Error: Could not connect to server"

I think I input IP address incorrectly. Now I can use SFTP by FilleZilla from my windows laptop. I will come back to update when I can not SFTP access the server again. I could not try FilleZilla from my Android phone sine FileZilla does not have Android version.

[TMzethar]

There are also Android apps that support SFTP. You can search on your own Android store