diff --git a/bootstrap b/bootstrap
index 7c56bab..16c1be5 100755
--- a/bootstrap
+++ b/bootstrap
@@ -101,7 +101,7 @@ extract(Binary) ->
 request(Url) ->
     HttpOptions = [{relaxed, true} | get_proxy_auth()],
 
-    case httpc:request(get, {Url, []},
+    case rebar_hermeticity:request(get, {Url, []},
                        HttpOptions,
                        [{body_format, binary}],
                        rebar) of
diff --git a/src/rebar_hermeticity.erl b/src/rebar_hermeticity.erl
new file mode 100644
index 0000000..8f6cc7d
--- /dev/null
+++ b/src/rebar_hermeticity.erl
@@ -0,0 +1,42 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+%% -------------------------------------------------------------------
+%%
+%% rebar: Erlang Build Tools
+%%
+%% Copyright (c) 2016 Eric Merritt (eric@merritt.tech)
+%%
+%% Permission is hereby granted, free of charge, to any person obtaining a copy
+%% of this software and associated documentation files (the "Software"), to deal
+%% in the Software without restriction, including without limitation the rights
+%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+%% copies of the Software, and to permit persons to whom the Software is
+%% furnished to do so, subject to the following conditions:
+%%
+%% The above copyright notice and this permission notice shall be included in
+%% all copies or substantial portions of the Software.
+%%
+%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+%% THE SOFTWARE.
+%% -------------------------------------------------------------------
+-module(rebar_hermeticity).
+
+-export([request/5]).
+
+-include("rebar.hrl").
+
+%% ====================================================================
+%% Public API
+%% ====================================================================
+
+request(Method, {Url, _Headers}, _HTTPOptions, _Options, _Profile) ->
+    ?ERROR("A request is being made that violates Nix hermicity "
+           "This request has been stopped. Details of the request "
+           "are as follows:", []),
+    ?ERROR("Request: ~p ~s", [Method, Url]),
+    erlang:halt(1).
diff --git a/src/rebar_pkg_resource.erl b/src/rebar_pkg_resource.erl
index d588f24..9ac8ad4 100644
--- a/src/rebar_pkg_resource.erl
+++ b/src/rebar_pkg_resource.erl
@@ -109,7 +109,7 @@ make_vsn(_) ->
 request(Url, ETag) ->
     HttpOptions = [{ssl, ssl_opts(Url)}, {relaxed, true} | rebar_utils:get_proxy_auth()],
 
-    case httpc:request(get, {Url, [{"if-none-match", ETag} || ETag =/= false]++[{"User-Agent", rebar_utils:user_agent()}]},
+    case rebar_hermeticity:request(get, {Url, [{"if-none-match", ETag} || ETag =/= false]++[{"User-Agent", rebar_utils:user_agent()}]},
                        HttpOptions,
                        [{body_format, binary}],
                        rebar) of
diff --git a/src/rebar_prv_update.erl b/src/rebar_prv_update.erl
index a019c5a..697cbab 100644
--- a/src/rebar_prv_update.erl
+++ b/src/rebar_prv_update.erl
@@ -38,6 +38,8 @@ init(State) ->
     {ok, State1}.
 
 -spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) -> {ok, State}.
+-ifdef(non_hermetic).
 do(State) ->
     try
         case rebar_packages:registry_dir(State) of
@@ -52,7 +54,7 @@ do(State) ->
                 case rebar_utils:url_append_path(CDN, ?REMOTE_REGISTRY_FILE) of
                     {ok, Url} ->
                         ?DEBUG("Fetching registry from ~p", [Url]),
-                        case httpc:request(get, {Url, [{"User-Agent", rebar_utils:user_agent()}]},
+                        case rebar_hermeticity:request(get, {Url, [{"User-Agent", rebar_utils:user_agent()}]},
                                            [], [{stream, TmpFile}, {sync, true}],
                                            rebar) of
                             {ok, saved_to_file} ->
@@ -76,6 +78,7 @@ do(State) ->
             ?DEBUG("Error creating package index: ~p ~p", [C, erlang:get_stacktrace()]),
             throw(?PRV_ERROR(package_index_write))
     end.
+-endif.
 
 -spec format_error(any()) -> iolist().
 format_error({package_parse_cdn, Uri}) ->