[Bug]: sshd no longer works

[ballo]

Problem description

This is on the latest F-Droid Termux on Android 15 on a POS Pixel 7.

I used to be able to set the phone to hotspot mode then ssh to the phone via port 8022. For reasons unknown this is now failing every so often. It fails for a long period of time then seems to clear up and allows me to use it again. The port is open according to nmap, and I can still use the phone via scrcpy (adb on port 5555), but when I attempt an ssh it prompts me for a password then fails to provide a shell nor can it pipe sockets via -L or -D. I have tried killing and restarting sshd as well as force quitting Termux to no avail. I'm pretty familiar with all things UNIX and this one has me stumped, so I'm guessing it's something specific to Termux or Android which has put me in this bind.

Steps to reproduce the behavior.

Unfortunately these kinds of problems are difficult to reproduce, but it is happening. I'm not doing anything fancy with Termux. I do have the termus-api app installed so I can monitor the battery level.

What is the expected behavior?

I should be able to ssh to my phone at all times. The phone is still responsive in that I can use adb/scrcpy so it hasn't crashed nor hardly used any memory

System information

• Termux application version: 0.118.1
• Android OS version: 15
• Device model: POS Pixel 7

[twaik]

Try to capture logs with logcat when it happens and post the logs here, I hope it will make a situation a bit more clear.

[ballo]

What would I be logging?

[twaik]

logcat.

[agnostic-apollo]

Could be related to Termux app being frozen by Android.

• https://github.com/termux/termux-packages/blob/site/site/pages/en/projects/docs/repos/main/packages/termux-tools/logcat/index.md#to-get-full-system-logs-of-other-apps-and-the-android-system
• termux-usb -l Command Hangs on Google Pixel 7 with Android 14 termux-api#638 (comment)

[ballo]

Could be related to Termux app being frozen by Android.

I don't know if this is relevant but I could use termux via scrcpy while this was happening.

[agnostic-apollo]

Then probably not related, could be network optimizations with screen off

[freebrowser1]

I have it sometimes as well (Termux 118.1, Android 14), but it is mostly due to screen off. Turning on the screen fixes it.
Always disable full battery optimizations for the Termux app. In rare cases I had to kick (reboot) my phone and it was fixed.
And are you sure sshd daemon is loaded ? nmap -v -Pn localhost should show open port 8022.
Let it be clear: in most cases I can ssh into my phone using either ssh in a terminal or a GUI sftp client (on Linux and macOS, I don't have Windows).

[twaik]

You still did not send logcat logs after running sshd.

[ballo]

My somewhat crappy work-around is to use scrcpy to gain access to the termux app, killall sshd, then run it again.

[Flexximilian]

Have you tried starting it as sshd -D on the command line (to prevent it from daemonizing), and seeing (a) what it prints to STDOUT/STDERR and (b) if having it as a process with an open window fixes the issue? Also, that way you can kill it easily using a simple CTRL-C. And you'll see if the process lives (and how long -- a prompt containing the time helps with that) or if it exists immediately.