diff --git a/apps/sdlan/include/dns_proxy.hrl b/apps/sdlan/include/dns_proxy.hrl
index 6ff16e7..7000b7f 100644
--- a/apps/sdlan/include/dns_proxy.hrl
+++ b/apps/sdlan/include/dns_proxy.hrl
@@ -8,6 +8,9 @@
 %%%-------------------------------------------------------------------
 -author("anlicheng").
 
+-define(PENDING_TAB, ets_dns_pending_queries).
+-define(PENDING_INDEX_TAB, ets_dns_expire_index).
+
 -record(dns_cache, {
     %% {Qname, QType, QClass}
     key,
diff --git a/apps/sdlan/src/dns_proxy/dns_pending_queries.erl b/apps/sdlan/src/dns_proxy/dns_pending_queries.erl
new file mode 100644
index 0000000..7bea076
--- /dev/null
+++ b/apps/sdlan/src/dns_proxy/dns_pending_queries.erl
@@ -0,0 +1,46 @@
+%%%-------------------------------------------------------------------
+%%% @author anlicheng
+%%% @copyright (C) 2025, <COMPANY>
+%%% @doc
+%%%
+%%% @end
+%%% Created : 16. 12月 2025 14:38
+%%%-------------------------------------------------------------------
+-module(dns_pending_queries).
+-author("anlicheng").
+-include("dns_proxy.hrl").
+
+%% API
+-export([new/0, put/3, take/1, delete/1]).
+
+-spec new() -> no_return().
+new() ->
+    ets:new(?PENDING_TAB, [set, public, {read_concurrency, true}, {write_concurrency, true}]),
+    ets:new(?PENDING_INDEX_TAB, [bag, public, {read_concurrency, true}, {write_concurrency, true}]).
+
+-spec put(Key :: any(), Value :: any(), TTL :: integer()) -> no_return().
+put(Key, Value, TTL) when is_integer(TTL) ->
+    ExpireAt = erlang:monotonic_time(millisecond) + TTL,
+    ets:insert(?PENDING_TAB, {Key, {Value, ExpireAt}}),
+    ets:insert(?PENDING_INDEX_TAB, {ExpireAt, Key}).
+
+-spec take(Key :: any()) -> error | {ok, Value :: any()}.
+take(Key) ->
+    case ets:lookup(?PENDING_TAB, Key) of
+        [{Key, {Value, ExpireAt}}] ->
+            ets:delete(?PENDING_TAB, Key),
+            ets:delete(?PENDING_INDEX_TAB, ExpireAt),
+            {ok, Value};
+        [] ->
+            error
+    end.
+
+-spec delete(Key :: any()) -> no_return().
+delete(Key) ->
+    case ets:lookup(?PENDING_TAB, Key) of
+        [{Key, {_Value, ExpireAt}}] ->
+            ets:delete(?PENDING_TAB, Key),
+            ets:delete(?PENDING_INDEX_TAB, ExpireAt);
+        [] ->
+            ok
+    end.
\ No newline at end of file
diff --git a/apps/sdlan/src/dns_proxy/dns_pending_scanner.erl b/apps/sdlan/src/dns_proxy/dns_pending_scanner.erl
new file mode 100644
index 0000000..ae9dac5
--- /dev/null
+++ b/apps/sdlan/src/dns_proxy/dns_pending_scanner.erl
@@ -0,0 +1,51 @@
+%%%-------------------------------------------------------------------
+%%% @author anlicheng
+%%% @copyright (C) 2025, <COMPANY>
+%%% @doc
+%%%
+%%% @end
+%%% Created : 16. 12月 2025 14:46
+%%%-------------------------------------------------------------------
+-module(dns_pending_scanner).
+-author("anlicheng").
+-include("dns_proxy.hrl").
+
+%% 每次最多清理的记录条数
+-define(MAX_NUM, 500).
+
+-record(state, {
+
+}).
+
+%% API
+-export([start_link/0, init/0]).
+
+start_link() ->
+    {ok, spawn_link(?MODULE, init, [])}.
+
+init() ->
+    cleaner_loop(#state{}).
+
+cleaner_loop(State) ->
+    Now = erlang:monotonic_time(millisecond),
+    do_cleanup(Now, ?MAX_NUM),
+    cleaner_loop(State).
+
+do_cleanup(Now, Max) ->
+    do_cleanup(Now, Max, ets:first(?PENDING_INDEX_TAB)).
+
+do_cleanup(_Now, 0, _Key) ->
+    ok;
+do_cleanup(_Now, _Max, '$end_of_table') ->
+    ok;
+do_cleanup(Now, Max, ExpireAt) when ExpireAt =< Now ->
+    case ets:lookup(?PENDING_INDEX_TAB, ExpireAt) of
+        [{ExpireAt, Key}] ->
+            ets:delete(?PENDING_INDEX_TAB, ExpireAt),
+            ets:delete(?PENDING_TAB, Key),
+            do_cleanup(Now, Max - 1, ets:next(?PENDING_INDEX_TAB, ExpireAt));
+        [] ->
+            do_cleanup(Now, Max - 1, ets:next(?PENDING_INDEX_TAB, ExpireAt))
+    end;
+do_cleanup(_Now, _Max, _ExpireAt) ->
+    ok.
\ No newline at end of file