sftp Problem in 2024b vs 2024a

Is this a known bug?

On a Mac with two network interfaces active:

in 2024a:

>> myConn = sftp('orange.stanford.edu', 'dwfedora');

>>

in 2024b:

>> myConn = sftp('orange.stanford.edu', 'dwfedora');

Error using sftp (line 9)

Could not open a connection to "sftp://orange.stanford.edu", port "22". Verify the supplied host.

If I then disconnect one of the interfaces, myConn is set without an error

the system networking utilities and libraries work fine, 2024a works fine. 2024b seems to have introduced a bug.

Is the network i/o library in matlab really touching the acutal network interfaces? Shouldn't it just open a socket like a real program?

[Saurabh]

Hi @Douglas,

Could you attach FTP logs by running following commands:

>> feature diagnosticSpec matlab::io::ftp.*=all
>> feature diagnosticDest file=logs.txt

Also, could you please provide the reproduction step that would be helpful to solve the issue.

Thanks.

[Swastik Sarkar]

Hi @Douglas,

Could you verify if you can perform basic network operations, such as a webread, when both network interfaces are active?

[Douglas]

Here is the requested trace.

webread also fails.

system("sftp user@host" works

[Walter Roberson]

Odd that the first two attempts to connect to 171.64.204.130 failed, and that there is a 9 second pause in the logs and the connection works afterwards ??

[Douglas]

No, not odd; irrelevant.

When I change the order of operations the matlab functions always fail and the system function always works.

[Walter Roberson]

@Douglas I am not sure what you are implying? Are you implying that the first two failures are logs when both network interfaces are active, and that the 9 seconds later is a log of when one of the network accesses has been deactivated?

[Douglas]

Let me go over the situation again.

Under 2024b, in a system with more than one active network interface, the io library is sometimes unable to make internet connections. When it fails, it fails again and again. Correcting the problem seems to involve some combination of rebooting the system and connecting it to some other network for a while.

Under 2024a, this does not happen. I can run 2024b in one window and 2024a in another window, and 2024a will succeed again and again while 2024b fails again and again.

At the same time when I use the OS internet utilities, it also works.

I can switch back and forth repeatedly between the system software and the two versions of Matlab, in different orders and with different intervals and 2024b fails and the system and 2024a succeed.

So I surmise there is a bug in 2024b.

[Douglas]

Addendum:

Once it has entered the broken state, if you disconnect one interface, 2024b will work again, but it will break again as soon as you plug the 2nd interface back in.

I have not been able to figure out what makes it stop working in the first place. Some days it will work for hours at a time unitl it doesn't. Other days, it breaks as soon as I hook the system up.

[Walter Roberson]

So.. nothing happened in those 9 seconds? You simply tried the run again, but the third time it worked?

[Swastik Sarkar]

Hi @Douglas,

I suggest reaching out to MathWorks Technical Support to report this bug.