-module(is_ipv4_address).
-export([is_ipv4_address/1]).

is_ipv4_address(InputString) ->
    Parts = string:split(InputString, ".", all),
    length(Parts) =:= 4 andalso lists:all(fun valid_octet/1, Parts).

valid_octet(V) ->
    case string:to_integer(V) of
        {Int, ""} when Int >= 0, Int =< 255 ->
            integer_to_list(Int) =:= V;
        _ ->
            false
    end.