Get Private IP Address

private_addr.erl

{ok, Interfaces} = inet:getifaddrs(),
Addresses = lists:map(fun({_, Props}) -> proplists:get_all_values(addr, Props) end, Interfaces),
Private_Addresses = lists:filter(fun({F,_,_,_}) -> lists:member(F, [10, 172, 192]); (_) -> false end, lists:flatten(Addresses)),
io:format("Private Addresses = ~p\n", [Private_Addresses]),
case Private_Addresses of
    [] -> io:format("Unable to start monitor listener, no private address was found.\n", []),
          undefined;
    _  -> {A, B, C, D} = lists:nth(1, Private_Addresses),
          IP_Address = lists:flatten(io_lib:format("~.10B.~.10B.~.10B.~.10B", [A, B, C, D])),
          io:format("Starting listener on ~s\n", [IP_Address]),
          IP_Address
end.