Getting the error {:error, :eacces} while trying to connect to an udp server on port 123

[maqbool]

I found the solution

What's the best way to serve restricted ports (e.g. 80, 443) with Phoenix?

The executable that’s actually opening the port is the BEAM VM. Start iex in one window, then run ps aux | grep beam in another to see the details of the process. In my case, the executable is /usr/lib/erlang/erts-7.2/bin/beam.smp. Try setting the capabilities on that file instead. Update: confirmed on Ubuntu 14.04. $ sudo setcap 'cap_net_bind_service=+ep' /usr/lib/erlang/erts-7.2/bin/beam.smp $ iex Erlang/OTP 18 [erts-7.2] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:fal…