So before anything I wanted to say that I am a root user and I installed the GNURoot application from google play. So I have been playing around with the GNURoot app for 2-3 days, and I thought that it would be fun to try and make a reverse tcp connection from my laptop to my phone. So these are the commands I used:

On my phone:

root@localhost:/# nc -lp 443

On my computer:

root@potato:~$ nc 443

But I keep getting this error on my phone:

Can't grab with bind : Permission denied

Google didn't help much, I know that for ports under 1024 you need admin/root access, but GNURoot never asked for it. What should I do

  • Ask the dev to implement it. From the user's end, there's nothing you can do: An app must ask for root access, simply "granting" that doesn't help.
    – Izzy
    Commented Sep 14, 2017 at 16:18
  • @Izzy I have tested it with ports 1024 and up and it works just fine
    – MarinB
    Commented Sep 14, 2017 at 16:24
  • If you're satisfied with that and consider it a solution, feel free to answer your own question and accept the answer then. You can of course include my above comment for completeness.
    – Izzy
    Commented Sep 14, 2017 at 16:27

1 Answer 1


So the answer to the question is to use ports above 1024 or as @Izzy suggested to ask the dev to implement root access (as an app must ask to perform root operations, simply "granting it permission" would not help as the app would not know to (properly) make use of it).

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