diff --git a/apps/dns_proxy/src/dns_handler.erl b/apps/dns_proxy/src/dns_handler.erl
index fd63def..f82a4f9 100644
--- a/apps/dns_proxy/src/dns_handler.erl
+++ b/apps/dns_proxy/src/dns_handler.erl
@@ -167,12 +167,9 @@ build_response(Query, #dns_cache{expire_at = ExpireAt, answers = Answers, author
     Now = os:system_time(second),
     RemainingTTL = ExpireAt - Now,
 
-    Adjust = fun(RR) -> RR#dns_rr{ttl = max(0, RemainingTTL)} end,
-    Answers2 = [Adjust(RR) || RR <- Answers],
-    Authority2 = [Adjust(RR) || RR <- Authority],
-
-    Additional0 = [Adjust(RR) || RR <- Additional],
-    Additional2 = add_opt_if_needed(Query, Additional0),
+    Answers2 = [adjust_ttl(RR, RemainingTTL) || RR <- Answers],
+    Authority2 = [adjust_ttl(RR, RemainingTTL) || RR <- Authority],
+    Additional2 = [adjust_ttl(RR, RemainingTTL) || RR <- Additional],
 
     Query#dns_message{
         qr = true,
@@ -182,20 +179,7 @@ build_response(Query, #dns_cache{expire_at = ExpireAt, answers = Answers, author
         additional = Additional2
     }.
 
-add_opt_if_needed(Query, Additional) ->
-    case dns_opt:find(Query#dns_message.additional) of
-        false ->
-            %% 客户端未使用 EDNS → 不在响应中加 OPT
-            Additional;
-        {ok, OptReq} ->
-            %% 客户端使用 EDNS → 构造自身的 OPT RR
-            UdpSize = dns_opt:udp_payload(OptReq),
-            DoBit  = dns_opt:do_bit(OptReq),
-
-            OptResp = dns_opt:make(UdpSize, DoBit),
-
-            %% 去除上游响应里的旧 OPT（如果有）
-            Additional2 = [RR || RR <- Additional, RR#dns_rr.type =/= opt],
-            %% 新的 OPT 一定放在 Additional 最后
-            Additional2 ++ [OptResp]
-    end.
\ No newline at end of file
+adjust_ttl(RR = #dns_rr{}, RemainingTTL) ->
+    RR#dns_rr{ttl = max(0, RemainingTTL)};
+adjust_ttl(RR, _RemainingTTL) ->
+    RR.
\ No newline at end of file
diff --git a/apps/dns_proxy/src/dns_opt.erl b/apps/dns_proxy/src/dns_opt.erl
deleted file mode 100644
index 725fb8a..0000000
--- a/apps/dns_proxy/src/dns_opt.erl
+++ /dev/null
@@ -1,46 +0,0 @@
-%%--------------------------------------------------------------------
-%% EDNS (OPT RR) Utility for dns_erlang
-%%--------------------------------------------------------------------
--module(dns_opt).
-
--export([find/1, make/2, udp_payload/1, do_bit/1]).
-
--include_lib("dns_erlang/include/dns.hrl").
-
-%%--------------------------------------------------------------------
-%% 查找 OPT RR（RR type = opt）
-%%--------------------------------------------------------------------
-find(RRs) ->
-    case lists:dropwhile(fun(RR) -> RR#dns_rr.type =/= opt end, RRs) of
-        [] ->
-            false;
-        [RR|_] ->
-            {ok, RR}
-    end.
-
-%%--------------------------------------------------------------------
-%% 获取 DO bit（TTL 的最高 bit）
-%%--------------------------------------------------------------------
-do_bit(RR) ->
-    (RR#dns_rr.ttl band 16#8000) =/= 0.
-
-%%--------------------------------------------------------------------
-%% 获取 UDP payload size（来自 class 字段）
-%%--------------------------------------------------------------------
-udp_payload(RR) ->
-    RR#dns_rr.class.
-
-%%--------------------------------------------------------------------
-%% 构造新的 OPT RR（符合 RFC6891）
-%% make(UdpPayloadSize, DoBit)
-%%--------------------------------------------------------------------
-make(UdpPayloadSize, DoBit) ->
-    TTL = if DoBit -> 16#8000; true -> 0 end,
-    #dns_rr{
-        name = <<>>,      % Root label
-        type = opt,
-        class = UdpPayloadSize,
-        ttl = TTL,
-        % No EDNS options by default
-        data = []
-    }.