diff --git a/.merlin b/.merlin
index 7d5942ab2..1363999e5 100644
--- a/.merlin
+++ b/.merlin
@@ -1,8 +1,8 @@
 PKG async async_kernel
 PKG re ipaddr uri base64 hashcons cstruct result cstruct.ppx
 PKG lwt mirage-profile cmdliner re.str lwt.uni uri.services ipaddr.unix
-PKG io-page duration mirage-time-lwt mirage-stack-lwt mirage-kv-lwt
-PKG oUnit pcap-format mirage-protocols mirage-kv io-page.unix
+PKG duration mirage-time-lwt mirage-stack-lwt mirage-kv-lwt
+PKG oUnit pcap-format mirage-protocols mirage-kv
 
 S lib
 S lib_test
diff --git a/_tags b/_tags
index dc7a554d4..b38be12d0 100644
--- a/_tags
+++ b/_tags
@@ -9,7 +9,7 @@ true : package(re re.str ipaddr uri base64 hashcons cstruct result)
 "lwt": include
 <lwt/*.{ml,mli}>: package(lwt mirage-profile)
 <lwt/dig_unix.*>: package(cmdliner lwt.unix uri.services ipaddr.unix lwt)
-<mirage/*.{ml,mli}>: package(io-page lwt duration mirage-time-lwt)
+<mirage/*.{ml,mli}>: package(lwt duration mirage-time-lwt)
 <mirage/*.{ml,mli}>: package(mirage-stack-lwt mirage-kv-lwt)
 
 <async/*.{ml,mli}>: package(async async_kernel threads), thread
@@ -20,7 +20,7 @@ true : package(re re.str ipaddr uri base64 hashcons cstruct result)
 "async": include
 <lib_test/unix/*>: package(lwt lwt.unix uri.services ipaddr.unix)
 <lib_test/ounit/*>: package(oUnit cstruct.ppx pcap-format lwt mirage-protocols)
-<lib_test/ounit/*>: package(mirage-stack-lwt mirage-time-lwt mirage-kv io-page)
+<lib_test/ounit/*>: package(mirage-stack-lwt mirage-time-lwt mirage-kv)
 <lib_test/ounit/*>: package(mirage-kv-lwt lwt.unix uri.services)
-<lib_test/ounit/*>: package(mirage-profile lwt ipaddr.unix duration io-page.unix)
-<lib_test/async/*>: package(async threads), thread
+<lib_test/ounit/*>: package(mirage-profile lwt ipaddr.unix duration)
+<lib_test/async/*>: package(async threads uri.services), thread
diff --git a/async/async_dns_resolver.ml b/async/async_dns_resolver.ml
index 53c34a54d..8d28f42b9 100644
--- a/async/async_dns_resolver.ml
+++ b/async/async_dns_resolver.ml
@@ -28,8 +28,8 @@ type result = Answer of DP.t | Err of exn
 
 type commfn = {
   log : Log.t option;
-  txfn    : Buf.t -> unit Deferred.t;
-  rxfn    : (Buf.t -> Packet.t option) -> DP.t Deferred.t;
+  txfn    : Cstruct.t -> unit Deferred.t;
+  rxfn    : (Cstruct.t -> Packet.t option) -> DP.t Deferred.t;
   timerfn : unit -> unit Deferred.t;
   cleanfn : unit -> unit Deferred.t;
 }
@@ -50,9 +50,9 @@ let rec send_req txfn timerfn q = function
       send_req txfn timerfn q (count - 1)
     end
 
-let send_pkt client { log; txfn; rxfn; timerfn; cleanfn } pkt =
+let send_pkt ?alloc client { log; txfn; rxfn; timerfn; cleanfn } pkt =
   let module R = (val client: CLIENT ) in
-  let cqpl = R.marshal pkt in
+  let cqpl = R.marshal ?alloc pkt in
   let resl = List.map cqpl ~f:begin fun (ctxt, q) -> Deferred.any [
       ((send_req txfn timerfn q 4) >>| fun () -> (Err (R.timeout ctxt)));
       (try_with (fun () -> rxfn (R.parse ctxt)) >>| function
@@ -78,19 +78,19 @@ let send_pkt client { log; txfn; rxfn; timerfn; cleanfn } pkt =
       find_answer errors rs
   in select [] resl
 
-let resolve ?(dnssec = false) client commfn q_class q_type q_name =
+let resolve ?alloc ?(dnssec = false) client commfn q_class q_type q_name =
   Monitor.try_with_or_error begin fun () ->
     let id = (let module R = (val client: CLIENT ) in R.get_id ()) in
     let q = Dns.Query.create ~id ~dnssec q_class q_type q_name in
-    send_pkt client commfn q
+    send_pkt ?alloc client commfn q
   end >>| fun r ->
   don't_wait_for (commfn.cleanfn ());
   r
 
-let gethostbyname ?(q_class=DP.Q_IN) ?(q_type=DP.Q_A) commfn name =
+let gethostbyname ?alloc ?(q_class=DP.Q_IN) ?(q_type=DP.Q_A) commfn name =
   let open DP in
   let domain = Name.of_string name in
-  resolve (module Dns.Protocol.Client) commfn q_class q_type domain >>|
+  resolve ?alloc (module Dns.Protocol.Client) commfn q_class q_type domain >>|
   Or_error.map ~f:begin fun r ->
     List.fold_right r.answers ~init:[] ~f:begin fun x a ->
       match x.rdata with
diff --git a/async/async_dns_resolver.mli b/async/async_dns_resolver.mli
index 4458170e6..4efebc861 100644
--- a/async/async_dns_resolver.mli
+++ b/async/async_dns_resolver.mli
@@ -24,13 +24,14 @@ open Dns
 
 type commfn = {
   log : Log.t option;
-  txfn : Buf.t -> unit Deferred.t;
-  rxfn : (Buf.t -> Packet.t option) -> Packet.t Deferred.t;
+  txfn : Cstruct.t -> unit Deferred.t;
+  rxfn : (Cstruct.t -> Packet.t option) -> Packet.t Deferred.t;
   timerfn : unit -> unit Deferred.t;
   cleanfn : unit -> unit Deferred.t;
 }
 
 val resolve :
+  ?alloc:(unit -> Cstruct.t) ->
   ?dnssec:bool ->
   (module Protocol.CLIENT) ->
   commfn ->
@@ -39,6 +40,7 @@ val resolve :
   Name.t -> Packet.t Deferred.Or_error.t
 
 val gethostbyname :
+  ?alloc:(unit -> Cstruct.t) ->
   ?q_class:Packet.q_class ->
   ?q_type:Packet.q_type ->
   commfn ->
diff --git a/async/async_dns_resolver_unix.ml b/async/async_dns_resolver_unix.ml
index fe711c137..cdd19f3b1 100644
--- a/async/async_dns_resolver_unix.ml
+++ b/async/async_dns_resolver_unix.ml
@@ -38,7 +38,7 @@ let cleanfn ?log sock () =
 
 let connect_to_resolver ?log ?(timeout=Time_ns.Span.of_int_sec 1) ?(port=53) addr =
   let sock = Socket.create (Socket.Type.udp) in
-  let addr = sockaddr addr port in
+  let addr = sockaddr addr ~port in
   Monitor.try_with_or_error
     (fun () -> Socket.connect_interruptible sock addr ~interrupt:(Clock_ns.after timeout)) >>= begin function
     | Error e ->
@@ -48,13 +48,13 @@ let connect_to_resolver ?log ?(timeout=Time_ns.Span.of_int_sec 1) ?(port=53) add
     | Ok (`Ok ac_sock) ->
       let txfn buf =
         let w = Writer.create (Socket.fd ac_sock) in
-        Writer.write_bigstring ~pos:0 ~len:(Buf.length buf) w buf;
+        Writer.write_bigstring ~pos:buf.Cstruct.off ~len:buf.Cstruct.len w buf.Cstruct.buffer;
         Writer.flushed w
       in
       let rec rxfn f =
         let r = Reader.create (Socket.fd ac_sock) in
         let handle_chunk (iobuf : ([ `Read | `Who_can_write of Core_kernel.Perms.me ], Iobuf.seek) Iobuf.t) =
-          match f @@ Iobuf.Consume.To_bigstring.subo (iobuf :> ([ `Read ], Iobuf.seek) Iobuf.t) with
+          match f @@ Cstruct.of_bigarray (Iobuf.Consume.To_bigstring.subo (iobuf :> ([ `Read ], Iobuf.seek) Iobuf.t)) with
           | None ->
             Option.iter log ~f:(fun log -> Log.error log "Received wrong data, retrying");
             return `Continue
diff --git a/doc/api.odocl b/doc/api.odocl
index 9100704be..9c543fd41 100644
--- a/doc/api.odocl
+++ b/doc/api.odocl
@@ -9,7 +9,6 @@ Zone
 Zone_lexer
 Zone_parser
 Resolvconf
-Buf
 Protocol
 Probe
 
diff --git a/lib/buf.ml b/lib/buf.ml
deleted file mode 100644
index 2ebcfe869..000000000
--- a/lib/buf.ml
+++ /dev/null
@@ -1,29 +0,0 @@
-(*
- * Copyright (c) 2013 David Sheets <sheets@alum.mit.edu>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- *
- *)
-
-module B = Bigarray
-module B1 = B.Array1
-
-type t = (char, B.int8_unsigned_elt, B.c_layout) B1.t
-
-let default_allocator () = Bigarray.(Array1.create char c_layout 4096)
-
-let create ?(alloc=default_allocator) len = B1.sub (alloc ()) 0 len
-let length = B1.dim
-let of_cstruct c = Cstruct.(B1.sub c.buffer c.off c.len)
-let shift b k = B1.sub b k (length b - k)
-let sub = B1.sub
diff --git a/lib/buf.mli b/lib/buf.mli
deleted file mode 100644
index 6dc758e4d..000000000
--- a/lib/buf.mli
+++ /dev/null
@@ -1,32 +0,0 @@
-(*
- * Copyright (c) 2013 David Sheets <sheets@alum.mit.edu>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- *
- *)
-
-(** Buffer handling for DNS packets *)
-
-(** A [t] is an externally managed Bigarray *)
-type t = (char, Bigarray.int8_unsigned_elt, Bigarray.c_layout) Bigarray.Array1.t
-
-(** [create ?alloc b] will allocate a buffer of [b] bytes, where the
-    maximum size is 4096 bytes.
-    If [alloc] is supplied then it will be used to allocate the memory
-    page instead of the default [malloc]-based Bigarray create function. *)
-val create : ?alloc:(unit -> t) -> int -> t
-
-val length : t -> int
-val of_cstruct : Cstruct.t -> t
-val shift : t -> int -> t
-val sub : t -> int -> int -> t
diff --git a/lib/dns.mlpack b/lib/dns.mlpack
index 838c8e6f4..7984f2215 100644
--- a/lib/dns.mlpack
+++ b/lib/dns.mlpack
@@ -9,7 +9,6 @@ Zone
 Zone_lexer
 Zone_parser
 Resolvconf
-Buf
 Protocol
 Dig
 Probe
diff --git a/lib/packet.ml b/lib/packet.ml
index f2411d48b..25baffe9c 100644
--- a/lib/packet.ml
+++ b/lib/packet.ml
@@ -1459,7 +1459,6 @@ let to_string d =
     (d.additionals ||> rr_to_string |> String.concat ",")
 
 let parse buf =
-  let buf = Cstruct.of_bigarray buf in
   let names = Hashtbl.create 32 in
   let parsen f base n buf typ =
     let rec aux acc n base buf =
@@ -1489,12 +1488,12 @@ let parse buf =
   (* eprintf "RX: %s\n%!" (to_string dns); *)
   dns
 
-let marshal txbuf dns =
+let marshal ?(alloc = fun () -> Cstruct.create 4096) dns =
+  let txbuf = alloc () in
   let marshaln f names base buf values =
     List.fold_left f (names, base, buf) values
   in
 
-  let txbuf = Cstruct.of_bigarray txbuf in
   set_h_id txbuf dns.id;
   set_h_detail txbuf (marshal_detail dns.detail);
   set_h_qdcount txbuf (List.length dns.questions);
@@ -1510,7 +1509,7 @@ let marshal txbuf dns =
   let names,base,buf = marshaln marshal_rr names base buf dns.authorities in
   let _,_,buf = marshaln marshal_rr names base buf dns.additionals in
 
-  let txbuf = Buf.sub txbuf.Cstruct.buffer 0 Cstruct.(len txbuf - len buf) in
+  let txbuf = Cstruct.(sub txbuf 0 (len txbuf - len buf)) in
   (* Cstruct.hexdump txbuf;   *)
   (* eprintf "TX: %s\n%!" (txbuf |> parse (Hashtbl.create 8) |> to_string); *)
   txbuf
diff --git a/lib/packet.mli b/lib/packet.mli
index d0f45cf45..01232abfc 100644
--- a/lib/packet.mli
+++ b/lib/packet.mli
@@ -356,10 +356,10 @@ type t = {
 }
 
 val to_string : t -> string
-val parse : Buf.t -> t
+val parse : Cstruct.t -> t
 
 (** The marshalling entry point, given a {! dns} structure.
 
     @return the marshalled packet
 *)
-val marshal : Buf.t -> t -> Buf.t
+val marshal : ?alloc:(unit -> Cstruct.t) -> t -> Cstruct.t
diff --git a/lib/protocol.ml b/lib/protocol.ml
index 840995c7c..fda5fe69e 100644
--- a/lib/protocol.ml
+++ b/lib/protocol.ml
@@ -22,8 +22,8 @@ module type CLIENT = sig
 
   val get_id : unit -> int
 
-  val marshal : ?alloc:(unit -> Buf.t) -> Packet.t -> (context * Buf.t) list
-  val parse : context -> Buf.t -> Packet.t option
+  val marshal : ?alloc:(unit -> Cstruct.t) -> Packet.t -> (context * Cstruct.t) list
+  val parse : context -> Cstruct.t -> Packet.t option
 
   val timeout : context -> exn
 end
@@ -37,7 +37,7 @@ module Client : CLIENT = struct
     Random.int (1 lsl 16)
 
   let marshal ?alloc q =
-    [q.Packet.id, Packet.marshal (Buf.create ?alloc 4096) q]
+    [q.Packet.id, Packet.marshal ?alloc q]
 
   let parse id buf =
     let pkt = Packet.parse buf in
@@ -51,8 +51,8 @@ module type SERVER = sig
 
   val query_of_context : context -> Packet.t
 
-  val parse   : Buf.t -> context option
-  val marshal : Buf.t -> context -> Packet.t -> Buf.t option
+  val parse   : Cstruct.t -> context option
+  val marshal : ?alloc:(unit -> Cstruct.t) -> context -> Packet.t -> Cstruct.t option
 
 end
 
@@ -70,6 +70,6 @@ module Server : SERVER with type context = Packet.t = struct
   let query_of_context x = x
 
   let parse buf = contain_exc "parse" (fun () -> Packet.parse buf)
-  let marshal buf _q response =
-    contain_exc "marshal" (fun () -> Packet.marshal buf response)
+  let marshal ?alloc _q response =
+    contain_exc "marshal" (fun () -> Packet.marshal ?alloc response)
 end
diff --git a/lib/protocol.mli b/lib/protocol.mli
index a8dd8405c..3a64fc9da 100644
--- a/lib/protocol.mli
+++ b/lib/protocol.mli
@@ -32,12 +32,12 @@ module type CLIENT = sig
       successful parse or timeout. With this behavior, it is easy to construct
       low-latency but network-environment-aware DNS resolvers.
   *)
-  val marshal : ?alloc:(unit -> Buf.t) -> Packet.t -> (context * Buf.t) list
+  val marshal : ?alloc:(unit -> Cstruct.t) -> Packet.t -> (context * Cstruct.t) list
 
   (** [parse ctxt buf] is the potential packet extracted out of [buf]
       with [ctxt]
   *)
-  val parse : context -> Buf.t -> Packet.t option
+  val parse : context -> Cstruct.t -> Packet.t option
 
   (** [timeout ctxt] is the exception resulting from a context [ctxt] that has
       timed-out
@@ -61,15 +61,15 @@ module type SERVER = sig
       @param buf message buffer
       @return parsed packet and context
   *)
-  val parse   : Buf.t -> context option
+  val parse   : Cstruct.t -> context option
 
   (** DNS wire format marshal function.
-      @param buf output resource
+      @param alloc allocator
       @param _q context
       @param response answer packet
       @return buffer to write
   *)
-  val marshal : Buf.t -> context -> Packet.t -> Buf.t option
+  val marshal : ?alloc:(unit -> Cstruct.t) -> context -> Packet.t -> Cstruct.t option
 end
 
 (** The default DNS server using the standard DNS protocol *)
diff --git a/lib_test/mirage-mdns/unikernel.ml b/lib_test/mirage-mdns/unikernel.ml
index 4977d4f28..5af2d1346 100644
--- a/lib_test/mirage-mdns/unikernel.ml
+++ b/lib_test/mirage-mdns/unikernel.ml
@@ -28,7 +28,6 @@ module Main (C:CONSOLE) (K:KV_RO) (S:STACKV4) = struct
     let open Mdns_responder in
     let udp = S.udpv4 s in
     let module Responder = Make(struct
-        let alloc () = (Io_page.get 1 :> Dns.Buf.t)
         let write (dest_ip,dest_port) txbuf =
           U.write ~source_port:listening_port ~dest_ip:dest_ip ~dest_port udp (Cstruct.of_bigarray txbuf)
         let sleep t = OS.Time.sleep t
diff --git a/lib_test/ounit/test_dns_server_mirage.ml b/lib_test/ounit/test_dns_server_mirage.ml
index 28fa487b5..920ec8541 100644
--- a/lib_test/ounit/test_dns_server_mirage.ml
+++ b/lib_test/ounit/test_dns_server_mirage.ml
@@ -27,8 +27,8 @@ let simulate_query
     detail= {qr=Query; opcode=Standard; aa=false; tc=false; rd=true; ra=false; rcode=NoError};
     questions=[question]; answers=[]; authorities=[]; additionals=[];
   } in
-  let buf = marshal (Dns.Buf.create 512) request |> Cstruct.of_bigarray in
-  let listener_thread = match MockStack.udpv4_listeners stack 53 with
+  let buf = marshal request in
+  let listener_thread = match MockStack.udpv4_listeners stack ~dst_port:53 with
     | None -> assert_failure "missing listener"
     | Some listener -> listener ~src:from_ip ~dst:to_ip ~src_port:from_port buf
   in
@@ -140,7 +140,7 @@ let tests =
           assert_equal ~printer:string_of_int 53 w.src_port;
           assert_ip client_ip w.dst;
           assert_equal ~printer:string_of_int 12345 w.dst_port;
-          let packet = parse (Dns.Buf.of_cstruct w.buf) in
+          let packet = parse w.buf in
           assert_packet ~prefix:"1" ~id:3848 packet
             {qr=Response; opcode=Standard; aa=true; tc=false; rd=true; ra=false; rcode=NoError}
             1 1 2 3;
@@ -170,7 +170,7 @@ let tests =
           assert_equal ~printer:string_of_int 53 w.src_port;
           assert_ip client_ip w.dst;
           assert_equal ~printer:string_of_int 12345 w.dst_port;
-          let packet = parse (Dns.Buf.of_cstruct w.buf) in
+          let packet = parse w.buf in
           assert_packet ~prefix:"2" ~id:19560 packet
             {qr=Response; opcode=Standard; aa=true; tc=false; rd=true; ra=false; rcode=NoError}
             1 1 2 3;
diff --git a/lib_test/ounit/test_mdns_resolver_mirage.ml b/lib_test/ounit/test_mdns_resolver_mirage.ml
index aae4c6011..5d954cb58 100644
--- a/lib_test/ounit/test_mdns_resolver_mirage.ml
+++ b/lib_test/ounit/test_mdns_resolver_mirage.ml
@@ -87,6 +87,8 @@ module StubIpv4 = struct
   type uipaddr = Ipaddr.t
   let to_uipaddr ip = Ipaddr.V4 ip
   let of_uipaddr = Ipaddr.to_v4
+
+  let mtu _ = 1500
 end
 
 
@@ -269,8 +271,8 @@ let simulate_response
     stack
   =
   let response = { id; detail; questions=[]; answers; authorities=[]; additionals=[]; } in
-  let buf = marshal (Dns.Buf.create 512) response |> Cstruct.of_bigarray in
-  let listener_thread = match MockStack.udpv4_listeners stack 5353 with
+  let buf = marshal response in
+  let listener_thread = match MockStack.udpv4_listeners ~dst_port:5353 stack with
     | None -> assert_failure "missing listener"
     | Some listener -> listener ~src:from_ip ~dst:to_ip ~src_port:from_port buf
   in
@@ -320,7 +322,7 @@ let tests =
         assert_equal ~printer:string_of_int 5353 w.src_port;
         assert_ip mdns_ip w.dst;
         assert_equal ~printer:string_of_int 5353 w.dst_port;
-        let packet = parse (Dns.Buf.of_cstruct w.buf) in
+        let packet = parse w.buf in
         (* AA bit MUST be zero; RA bit MUST be zero; RD bit SHOULD be zero *)
         let expected = "0000 Query:0 na:c:nr:rn 0 <qs:valid.local. <A|IN>> <an:> <au:> <ad:>" in
         assert_equal ~msg:"packet" ~printer:(fun s -> s) expected (to_string packet);
@@ -372,7 +374,7 @@ let tests =
         assert_equal ~printer:string_of_int 5353 w2.src_port;
         assert_ip mdns_ip w2.dst;
         assert_equal ~printer:string_of_int 5353 w2.dst_port;
-        let query_packet = parse (Dns.Buf.of_cstruct w2.buf) in
+        let query_packet = parse w2.buf in
         (* AA bit MUST be zero; RA bit MUST be zero; RD bit SHOULD be zero *)
         let expected = "0000 Query:0 na:c:nr:rn 0 <qs:valid.local. <A|IN>> <an:> <au:> <ad:>" in
         assert_equal ~msg:"query_packet" ~printer:(fun s -> s) expected (to_string query_packet);
@@ -409,7 +411,7 @@ let tests =
         assert_equal ~printer:string_of_int 5353 w.src_port;
         assert_ip mdns_ip w.dst;
         assert_equal ~printer:string_of_int 5353 w.dst_port;
-        let packet = parse (Dns.Buf.of_cstruct w.buf) in
+        let packet = parse w.buf in
         (* AA bit MUST be zero; RA bit MUST be zero; RD bit SHOULD be zero *)
         let expected = "0000 Query:0 na:c:nr:rn 0 <qs:valid.local. <A|IN>> <an:> <au:> <ad:>" in
         assert_equal ~msg:"packet" ~printer:(fun s -> s) expected (to_string packet);
diff --git a/lib_test/ounit/test_mdns_responder.ml b/lib_test/ounit/test_mdns_responder.ml
index 8b40eef2b..67de02ae5 100644
--- a/lib_test/ounit/test_mdns_responder.ml
+++ b/lib_test/ounit/test_mdns_responder.ml
@@ -14,8 +14,6 @@ let load_file path =
 let assert_range low high actual =
   assert_bool (sprintf "%f not in range %f <= x < %f" actual low high) (low <= actual && actual < high)
 
-let allocfn () = Bigarray.Array1.create Bigarray.char Bigarray.c_layout 4096
-
 open Dns
 open Packet
 
@@ -88,7 +86,7 @@ let tests =
     "q-A-AAAA" >:: (fun test_ctxt ->
         let txlist = ref [] in
         let module MockTransport = struct
-          let alloc () = allocfn ()
+          let alloc () = Cstruct.create 4096
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             Lwt.return ()
@@ -127,7 +125,7 @@ let tests =
     "q-legacy" >:: (fun test_ctxt ->
         let txlist = ref [] in
         let module MockTransport = struct
-          let alloc () = allocfn ()
+          let alloc () = Cstruct.create 4096
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             Lwt.return ()
@@ -173,7 +171,7 @@ let tests =
     "q-PTR-first" >:: (fun test_ctxt ->
         let txlist = ref [] in
         let module MockTransport = struct
-          let alloc () = allocfn ()
+          let alloc () = Cstruct.create 4096
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             Lwt.return ()
@@ -253,7 +251,7 @@ let tests =
 
     "q-PTR-known" >:: (fun test_ctxt ->
         let module MockTransport = struct
-          let alloc () = allocfn ()
+          let alloc () = Cstruct.create 4096
           let write addr buf =
             assert_failure "write shouldn't be called"
           let sleep t =
@@ -275,7 +273,7 @@ let tests =
         let txlist = ref [] in
         let sleepl = ref [] in
         let module MockTransport = struct
-          let alloc () = allocfn ()
+          let alloc () = Cstruct.create 4096
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             Lwt.return ()
@@ -317,7 +315,7 @@ let tests =
         let cond = Lwt_condition.create () in
         let sleepl = ref [] in
         let module MockTransport = struct
-          let alloc () = allocfn ()
+          let alloc () = Cstruct.create 4096
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             Lwt.return ()
@@ -387,8 +385,8 @@ let tests =
         let cond = Lwt_condition.create () in
         let sleepl = ref [] in
         let module MockTransport = struct
+          let alloc () = Cstruct.create 4096
           open Lwt
-          let alloc () = allocfn ()
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             return_unit
@@ -429,7 +427,7 @@ let tests =
           detail= {qr=Response; opcode=Standard; aa=true; tc=false; rd=false; ra=false; rcode=NoError};
           questions=[]; answers=[answer]; authorities=[]; additionals=[];
         } in
-        let response_buf = marshal (Dns.Buf.create 512) response in
+        let response_buf = marshal response in
         let _ = Responder.process responder ~src:(response_src_ip, 5353) ~dst:txaddr response_buf in
 
         (* A new probe cycle begins *)
@@ -453,8 +451,8 @@ let tests =
         let cond = Lwt_condition.create () in
         let sleepl = ref [] in
         let module MockTransport = struct
+          let alloc () = Cstruct.create 4096
           open Lwt
-          let alloc () = allocfn ()
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             return_unit
@@ -490,7 +488,7 @@ let tests =
           detail= {qr=Response; opcode=Standard; aa=true; tc=false; rd=false; ra=false; rcode=NoError};
           questions=[]; answers=[answer]; authorities=[]; additionals=[];
         } in
-        let response_buf = marshal (Dns.Buf.create 512) response in
+        let response_buf = marshal response in
         let _ = Responder.process responder ~src:(response_src_ip, 5353) ~dst:txaddr response_buf in
 
         (* Verify the second probe *)
@@ -539,8 +537,8 @@ let tests =
         let cond = Lwt_condition.create () in
         let sleepl = ref [] in
         let module MockTransport = struct
+          let alloc () = Cstruct.create 4096
           open Lwt
-          let alloc () = allocfn ()
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             return_unit
@@ -584,7 +582,7 @@ let tests =
           detail= {qr=Query; opcode=Standard; aa=false; tc=false; rd=false; ra=false; rcode=NoError};
           questions=[question]; answers=[]; authorities=[auth]; additionals=[];
         } in
-        let query_buf = marshal (Dns.Buf.create 512) query in
+        let query_buf = marshal query in
         let _ = Responder.process responder ~src:(conflict_src_ip, 5353) ~dst:txaddr query_buf in
 
         (* One-second delay before restarting the probe cycle *)
@@ -615,7 +613,7 @@ let tests =
         let txlist = ref [] in
         let sleepl = ref [] in
         let module MockTransport = struct
-          let alloc () = allocfn ()
+          let alloc () = Cstruct.create 4096
           let write addr buf =
             txlist := (addr, buf) :: !txlist;
             Lwt.return ()
diff --git a/lib_test/ounit/test_packet.ml b/lib_test/ounit/test_packet.ml
index c2a060037..c922fc07d 100644
--- a/lib_test/ounit/test_packet.ml
+++ b/lib_test/ounit/test_packet.ml
@@ -57,24 +57,14 @@ let load_packet path =
     assert_equal 4 version;
     assert_equal 17 (get_ipv4_proto ip);
     let udp = Cstruct.shift ip sizeof_ipv4 in
-    let body = Cstruct.shift udp sizeof_udpv4 in
-    Dns.Buf.of_cstruct body
+    Cstruct.shift udp sizeof_udpv4
   | None ->
     assert_failure "No packets"
 
 let hexdump ibuf =
-  let n = Dns.Buf.length ibuf in
-  let obuf = Buffer.create (3 * n) in
-  let rec acc i =
-    let ch = (int_of_char ibuf.{i}) in
-    Buffer.add_char obuf (if ch < 32 || ch >= 127 then '.' else ibuf.{i});
-    Buffer.add_string obuf (sprintf "%.2x " ch);
-    if i mod 16 = 15 then Buffer.add_char obuf '\n';
-    if i < n - 1 then acc (i + 1);
-  in
-  if n >= 1 then acc 0;
-  if n mod 16 != 15 then Buffer.add_char obuf '\n';
-  Buffer.contents obuf
+  let b = Buffer.create 16 in
+  Cstruct.hexdump_to_buffer b ibuf ;
+  Buffer.contents b
 
 open Dns
 open Packet
@@ -117,8 +107,8 @@ let tests =
             id=0x930b; detail; questions=[q];
             answers=[]; authorities=[]; additionals=[];
           } in
-        let buf = marshal (Dns.Buf.create 512) packet in
-        assert_equal ~printer:hexdump raw buf
+        let buf = marshal packet in
+        assert_equal ~cmp:Cstruct.equal ~printer:hexdump raw buf
     );
 
     "parse-dns-r-A" >:: (fun test_ctxt ->
@@ -188,8 +178,8 @@ let tests =
             id=0x930b; detail; questions=[q];
             answers; authorities=[]; additionals=[];
           } in
-        let buf = marshal (Dns.Buf.create 512) packet in
-        assert_equal ~printer:hexdump raw buf
+        let buf = marshal packet in
+        assert_equal ~cmp:Cstruct.equal ~printer:hexdump raw buf
     );
 
     "parse-mdns-q-A" >:: (fun test_ctxt ->
@@ -230,8 +220,8 @@ let tests =
             id=0; detail; questions=[q];
             answers=[]; authorities=[]; additionals=[];
           } in
-        let buf = marshal (Dns.Buf.create 512) packet in
-        assert_equal ~printer:hexdump raw buf
+        let buf = marshal packet in
+        assert_equal ~cmp:Cstruct.equal ~printer:hexdump raw buf
     );
 
     "parse-mdns-r-A" >:: (fun test_ctxt ->
@@ -275,8 +265,8 @@ let tests =
             id=0; detail; questions=[];
             answers=[a]; authorities=[]; additionals=[];
           } in
-        let buf = marshal (Dns.Buf.create 512) packet in
-        assert_equal ~printer:hexdump raw buf
+        let buf = marshal packet in
+        assert_equal ~cmp:Cstruct.equal ~printer:hexdump raw buf
     );
 
     "q_unicast" >:: (fun test_ctxt ->
@@ -294,7 +284,7 @@ let tests =
             id=0; detail; questions=[q];
             answers=[]; authorities=[]; additionals=[];
           } in
-        let buf = marshal (Dns.Buf.create 512) packet in
+        let buf = marshal packet in
         let parsed = parse buf in
         let q = List.hd parsed.questions in
         assert_equal Q_mDNS_Unicast q.q_unicast
diff --git a/lwt/dns_resolver.ml b/lwt/dns_resolver.ml
index 5f26acafa..cde0e6576 100644
--- a/lwt/dns_resolver.ml
+++ b/lwt/dns_resolver.ml
@@ -27,8 +27,8 @@ module DP = Packet
 type result = Answer of DP.t | Error of exn
 
 type commfn = {
-  txfn    : Dns.Buf.t -> unit Lwt.t;
-  rxfn    : (Dns.Buf.t -> Dns.Packet.t option) -> DP.t Lwt.t;
+  txfn    : Cstruct.t -> unit Lwt.t;
+  rxfn    : (Cstruct.t -> Dns.Packet.t option) -> DP.t Lwt.t;
   timerfn : unit -> unit Lwt.t;
   cleanfn : unit -> unit Lwt.t;
 }
@@ -41,7 +41,7 @@ let rec send_req txfn timerfn q =
     timerfn () >>= fun () ->
     send_req txfn timerfn q (count - 1)
 
-let send_pkt ?alloc client ({ txfn; rxfn; timerfn; cleanfn }) pkt =
+let send_pkt client ?alloc ({ txfn; rxfn; timerfn; cleanfn }) pkt =
   let module R = (val client : CLIENT) in
   let cqpl = R.marshal ?alloc pkt in
   let resl = List.map (fun (ctxt,q) ->
@@ -73,7 +73,7 @@ let send_pkt ?alloc client ({ txfn; rxfn; timerfn; cleanfn }) pkt =
 
 let resolve_pkt client ?alloc (commfn:commfn) pkt =
   Lwt.catch (fun () ->
-      send_pkt ?alloc client commfn pkt
+      send_pkt client ?alloc commfn pkt
       >>= fun r -> commfn.cleanfn ()
       >>= fun () -> Lwt.return r)
     (function exn ->
@@ -97,7 +97,7 @@ let gethostbyname
     name =
   let open DP in
   let domain = Name.of_string name in
-  resolve ?alloc (module Dns.Protocol.Client) commfn q_class q_type domain
+  resolve (module Dns.Protocol.Client) ?alloc commfn q_class q_type domain
   >|= fun r ->
   List.fold_left (fun a x ->
       match x.rdata with
@@ -115,7 +115,7 @@ let gethostbyaddr
   =
   let addr = Name.of_ipaddr (Ipaddr.V4 addr) in
   let open DP in
-  resolve ?alloc (module Dns.Protocol.Client) commfn q_class q_type addr
+  resolve (module Dns.Protocol.Client) ?alloc commfn q_class q_type addr
   >|= fun r ->
   List.fold_left (fun a x ->
       match x.rdata with |PTR n -> (Name.to_string n)::a |_->a
diff --git a/lwt/dns_resolver.mli b/lwt/dns_resolver.mli
index 26cdab75a..54fc7e11b 100644
--- a/lwt/dns_resolver.mli
+++ b/lwt/dns_resolver.mli
@@ -17,10 +17,10 @@
  *)
 
 type commfn = {
-  txfn    : Dns.Buf.t -> unit Lwt.t;
+  txfn    : Cstruct.t -> unit Lwt.t;
   (** [txfn buf] resolves when [buf] has been transmitted. *)
 
-  rxfn    : (Dns.Buf.t -> Dns.Packet.t option) -> Dns.Packet.t Lwt.t;
+  rxfn    : (Cstruct.t -> Dns.Packet.t option) -> Dns.Packet.t Lwt.t;
   (** [rxfn parse] resolves to a packet processed by [parse] after it
       has been received. *)
 
@@ -37,7 +37,7 @@ type commfn = {
 
 val resolve_pkt :
   (module Dns.Protocol.CLIENT) ->
-  ?alloc:(unit -> Dns.Buf.t) ->
+  ?alloc:(unit -> Cstruct.t) ->
   commfn -> Dns.Packet.t ->
   Dns.Packet.t Lwt.t
 (** [resolve_pkt client ?alloc commfn packet] will attempt resolution
@@ -54,7 +54,7 @@ val resolve_pkt :
 
 val resolve : 
   (module Dns.Protocol.CLIENT) ->
-  ?alloc:(unit -> Dns.Buf.t) ->
+  ?alloc:(unit -> Cstruct.t) ->
   ?dnssec:bool ->
   commfn -> Dns.Packet.q_class -> 
   Dns.Packet.q_type -> 
@@ -65,13 +65,13 @@ val resolve :
     [name] and then attempt to resolve it by calling {!resolve_pkt}. *)
 
 val gethostbyname :
-  ?alloc:(unit -> Dns.Buf.t) ->
+  ?alloc:(unit -> Cstruct.t) ->
   ?q_class:Dns.Packet.q_class ->
   ?q_type:Dns.Packet.q_type -> commfn ->
   string -> Ipaddr.t list Lwt.t
 
 val gethostbyaddr :
-  ?alloc:(unit -> Dns.Buf.t) ->
+  ?alloc:(unit -> Cstruct.t) ->
   ?q_class:Dns.Packet.q_class ->
   ?q_type:Dns.Packet.q_type -> commfn ->
   Ipaddr.V4.t -> string list Lwt.t
diff --git a/lwt/dns_resolver_unix.ml b/lwt/dns_resolver_unix.ml
index 797ec1d15..b58648a97 100644
--- a/lwt/dns_resolver_unix.ml
+++ b/lwt/dns_resolver_unix.ml
@@ -56,13 +56,13 @@ let connect_to_resolver server port =
       ) in
   let timerfn () = Lwt_unix.sleep 5.0 in
   let txfn buf =
-    Lwt_bytes.sendto ofd buf 0 (Dns.Buf.length buf) [] dst
+    Cstruct.(Lwt_bytes.sendto ofd buf.buffer buf.off buf.len [] dst)
     >>= fun _ -> Lwt.return_unit in
   let rec rxfn f =
-    let buf = Dns.Buf.create buflen in
-    Lwt_bytes.recvfrom ofd buf 0 buflen []
+    let buf = Cstruct.create buflen in
+    Cstruct.(Lwt_bytes.recvfrom ofd buf.buffer buf.off buf.len [])
     >>= fun (len, sa) ->
-    let buf = Dns.Buf.sub buf 0 len in
+    let buf = Cstruct.sub buf 0 len in
     match f buf with
     | None -> rxfn f
     | Some r -> Lwt.return r
diff --git a/lwt/dns_server.ml b/lwt/dns_server.ml
index 2ad4fae7f..9c5a5c1cc 100644
--- a/lwt/dns_server.ml
+++ b/lwt/dns_server.ml
@@ -44,9 +44,9 @@ let compose process backup ~src ~dst packet =
       | _ -> backup ~src ~dst packet)
   | None -> backup ~src ~dst packet
 
-let process_query buf len obuf src dst processor =
+let process_query ?alloc buf len src dst processor =
   let module Processor = (val processor : PROCESSOR) in
-  match Processor.parse (Dns.Buf.sub buf 0 len) with
+  match Processor.parse (Cstruct.sub buf 0 len) with
   |None -> Lwt.return_none
   |Some ctxt ->
     Processor.process ~src ~dst ctxt >|= function
@@ -54,7 +54,7 @@ let process_query buf len obuf src dst processor =
     |Some answer ->
       let query = Processor.query_of_context ctxt in
       let response = Dns.Query.response_of_answer query answer in
-      Processor.marshal obuf ctxt response
+      Processor.marshal ?alloc ctxt response
 
 let processor_of_process process : Dns.Packet.t processor =
   let module P = struct
diff --git a/lwt/dns_server.mli b/lwt/dns_server.mli
index 34d8846c4..a4dba66e0 100644
--- a/lwt/dns_server.mli
+++ b/lwt/dns_server.mli
@@ -55,9 +55,9 @@ type 'a processor = (module PROCESSOR with type context = 'a)
 	an {!rcode} other than {!NoError} in which case it becomes [backup_process]. *)
 val compose: Dns.Packet.t process -> Dns.Packet.t process -> Dns.Packet.t process
 
-(** [process_query ibuf ibuflen obuf src dst processor] *)
-val process_query: Dns.Buf.t -> int -> Dns.Buf.t -> ip_endpoint -> ip_endpoint -> 
-  (module PROCESSOR) -> Dns.Buf.t option Lwt.t
+(** [process_query ?alloc ibuf ibuflen src dst processor] *)
+val process_query: ?alloc:(unit -> Cstruct.t) -> Cstruct.t -> int -> ip_endpoint -> ip_endpoint -> 
+  (module PROCESSOR) -> Cstruct.t option Lwt.t
 
 (** Returns a packet processor module by combining {!Dns.Protocol.Server} with
     the specified packet processing function. *)
diff --git a/lwt/dns_server_unix.ml b/lwt/dns_server_unix.ml
index 60de1450d..edf58467f 100644
--- a/lwt/dns_server_unix.ml
+++ b/lwt/dns_server_unix.ml
@@ -48,8 +48,6 @@ let eventual_process_of_zonefiles zonefiles =
   ) zonefiles
   >|= process_of_zonebufs
 
-let bufsz = 4096
-
 let ipaddr_of_sockaddr =
   function
   | Unix.ADDR_UNIX _ -> Lwt.fail (Failure "Unix domain sockets not supported")
@@ -57,27 +55,22 @@ let ipaddr_of_sockaddr =
 
 let listen ~fd ~src ~processor =
   let cont = ref true in
-  let bufs = Lwt_pool.create 64 (fun () -> Lwt.return (Dns.Buf.create bufsz)) in
   ipaddr_of_sockaddr src
   >>= fun src ->
   let rec loop () =
     if not !cont then Lwt.return_unit
     else
-      Lwt_pool.use bufs
-        (fun buf ->
-           Lwt_bytes.recvfrom fd buf 0 bufsz []
-           >>= fun (len, dst) ->
-           (* TODO Process in a background thread; should be a bounded queue *)
-           Lwt.async (fun () ->
-               ipaddr_of_sockaddr dst
-               >>= fun dst' ->
-               process_query buf len buf src dst' processor >>= function
-               | None -> Lwt.return_unit
-               | Some buf ->
-                   Lwt_bytes.sendto fd buf 0 (Dns.Buf.length buf) [] dst
-                   >>= fun _ -> Lwt.return_unit);
-           Lwt.return_unit)
-      >>= fun () ->
+      let buf = Cstruct.create 4096 in
+      Cstruct.(Lwt_bytes.recvfrom fd buf.buffer buf.off buf.len [])
+      >>= fun (len, dst) ->
+      (* TODO Process in a background thread; should be a bounded queue *)
+      Lwt.async (fun () ->
+          ipaddr_of_sockaddr dst >>= fun dst' ->
+          process_query buf len src dst' processor >>= function
+          | None -> Lwt.return_unit
+          | Some buf ->
+            Cstruct.(Lwt_bytes.sendto fd buf.buffer buf.off buf.len [] dst)
+            >>= fun _ -> Lwt.return_unit);
       loop ()
   in
   Lwt.async loop;
diff --git a/lwt/mdns_responder.ml b/lwt/mdns_responder.ml
index fd65cece1..1c61f0b8b 100644
--- a/lwt/mdns_responder.ml
+++ b/lwt/mdns_responder.ml
@@ -26,8 +26,8 @@ module Probe = Dns.Probe
 type ip_endpoint = Ipaddr.V4.t * int
 
 module type TRANSPORT = sig
-  val alloc : unit -> Dns.Buf.t
-  val write : ip_endpoint -> Dns.Buf.t -> unit Lwt.t
+  val alloc : unit -> Cstruct.t
+  val write : ip_endpoint -> Cstruct.t -> unit Lwt.t
   val sleep : float -> unit Lwt.t
 end
 
@@ -230,8 +230,7 @@ module Make (Transport : TRANSPORT) = struct
 
   let rec probe_forever t action first first_wakener =
     let send_action packet ip port =
-      let obuf = Transport.alloc () in
-      match Dns.Protocol.contain_exc "marshal" (fun () -> DP.marshal obuf packet) with
+      match Dns.Protocol.contain_exc "marshal" (fun () -> DP.marshal ~alloc:Transport.alloc packet) with
       | None -> Lwt.return_unit
       | Some buf -> Transport.write (ip, port) buf
     in
@@ -349,8 +348,7 @@ module Make (Transport : TRANSPORT) = struct
       Lwt.return_unit
     else
       (* TODO: limit the response packet size *)
-      let obuf = Transport.alloc () in
-      match DS.marshal obuf fake_query response with
+      match DS.marshal ~alloc:Transport.alloc fake_query response with
       | None -> Lwt.return_unit
       | Some obuf -> write_repeat (dest_host,dest_port) obuf repeat 1.0
 
@@ -429,8 +427,7 @@ module Make (Transport : TRANSPORT) = struct
           (* Possible delay before responding *)
           get_delay legacy response >>= fun () ->
           (* TODO: limit the response packet size *)
-          let obuf = Transport.alloc () in
-          match DS.marshal obuf query response with
+          match DS.marshal ~alloc:Transport.alloc query response with
           | None -> Lwt.return_unit
           | Some obuf ->
             (* RFC 6762 section 11 - TODO: send with IP TTL = 255 *)
diff --git a/lwt/mdns_responder.mli b/lwt/mdns_responder.mli
index 5c7e3cc63..73a460830 100644
--- a/lwt/mdns_responder.mli
+++ b/lwt/mdns_responder.mli
@@ -51,8 +51,8 @@ type ip_endpoint = Ipaddr.V4.t * int
 
 (** Encapsulates the dependencies that the responder requires for performing I/O. *)
 module type TRANSPORT = sig
-  val alloc : unit -> Dns.Buf.t
-  val write : ip_endpoint -> Dns.Buf.t -> unit Lwt.t
+  val alloc : unit -> Cstruct.t
+  val write : ip_endpoint -> Cstruct.t -> unit Lwt.t
   val sleep : float -> unit Lwt.t
 end
 
@@ -92,7 +92,7 @@ module Make : functor (Transport : TRANSPORT) -> sig
       mDNS queries, but it also parses responses to detect
       conflicts with unique records.
   *)
-  val process : t -> src:ip_endpoint -> dst:ip_endpoint -> Dns.Buf.t -> unit Lwt.t
+  val process : t -> src:ip_endpoint -> dst:ip_endpoint -> Cstruct.t -> unit Lwt.t
 
   (** Call this function to permanently stop the probe thread,
       to shut down the responder.
diff --git a/mirage-dns.opam b/mirage-dns.opam
index 347e1a270..56048fcb8 100644
--- a/mirage-dns.opam
+++ b/mirage-dns.opam
@@ -22,7 +22,6 @@ depends: [
   "mirage-kv-lwt"
   "mirage-time-lwt"
   "duration"
-  "io-page"
   "lwt"
   "mirage-profile"
 ]
diff --git a/mirage/dns_resolver_mirage.ml b/mirage/dns_resolver_mirage.ml
index 95263e2f6..8531d35eb 100644
--- a/mirage/dns_resolver_mirage.ml
+++ b/mirage/dns_resolver_mirage.ml
@@ -111,8 +111,7 @@ module Make(Time:Mirage_time_lwt.S)(S:Mirage_stack_lwt.V4) = struct
       let cleanfn () = return () in
       S.listen_udpv4 s ~port:src_port callback;
       let rec txfn buf =
-        Cstruct.of_bigarray buf |>
-        S.UDPV4.write ~src_port ~dst ~dst_port udp >>= function
+        S.UDPV4.write ~src_port ~dst ~dst_port udp buf >>= function
         | Error e ->
           Fmt.kstrf fail_with
             "Attempting to communicate with remote resolver: %a"
@@ -122,7 +121,7 @@ module Make(Time:Mirage_time_lwt.S)(S:Mirage_stack_lwt.V4) = struct
       let rec rxfn f =
         Lwt_mvar.take mvar
         >>= fun buf ->
-        match f (Dns.Buf.of_cstruct buf) with
+        match f buf with
         | None -> rxfn f
         | Some packet -> return packet
       in
@@ -130,27 +129,25 @@ module Make(Time:Mirage_time_lwt.S)(S:Mirage_stack_lwt.V4) = struct
       Hashtbl.add res endp commfn;
       commfn
 
-  let alloc () = (Io_page.get 1 :> Dns.Buf.t)
-
   let resolve client
       s server dns_port
       (q_class:DP.q_class) (q_type:DP.q_type)
       (q_name:Name.t) =
     let commfn = connect_to_resolver s (server,dns_port) in
-    resolve ~alloc client commfn q_class q_type q_name
+    resolve client commfn q_class q_type q_name
 
   let gethostbyname
       s ?(server = default_ns) ?(dns_port = default_port)
       ?(q_class:DP.q_class = DP.Q_IN) ?(q_type:DP.q_type = DP.Q_A)
       name =
     let commfn = connect_to_resolver s (server,dns_port) in
-    gethostbyname ~alloc ~q_class ~q_type commfn name
+    gethostbyname ~q_class ~q_type commfn name
 
   let gethostbyaddr
       s ?(server = default_ns) ?(dns_port = default_port)
       ?(q_class:DP.q_class = DP.Q_IN) ?(q_type:DP.q_type = DP.Q_PTR)
       addr =
     let commfn = connect_to_resolver s (server,dns_port) in
-    gethostbyaddr ~alloc ~q_class ~q_type commfn addr
+    gethostbyaddr ~q_class ~q_type commfn addr
 
 end
diff --git a/mirage/dns_server_mirage.ml b/mirage/dns_server_mirage.ml
index 9a8ed2bd9..b99c924b3 100644
--- a/mirage/dns_server_mirage.ml
+++ b/mirage/dns_server_mirage.ml
@@ -58,19 +58,16 @@ module Make(K:Mirage_kv_lwt.RO)(S:Mirage_stack_lwt.V4) = struct
   let serve_with_processor t ~port ~processor =
     let udp = S.udpv4 t.s in
     let listener ~src ~dst ~src_port buf =
-      let ba = Cstruct.to_bigarray buf in
       let src' = (Ipaddr.V4 dst), port in
       let dst' = (Ipaddr.V4 src), src_port in
-      let obuf = (Io_page.get 1 :> Dns.Buf.t) in
-      process_query ba (Dns.Buf.length ba) obuf src' dst' processor
+      process_query buf (Cstruct.len buf) src' dst' processor
       >>= function
       | None -> return ()
       | Some rba ->
-        let rbuf = Cstruct.of_bigarray rba in
         (* Do not attempt to retry if serving failed *)
-        S.UDPV4.write ~src_port:port ~dst:src ~dst_port:src_port udp rbuf >|= fun _ -> ()
+        S.UDPV4.write ~src_port:port ~dst:src ~dst_port:src_port udp rba >|= fun _ -> ()
     in
-    S.listen_udpv4 t.s port listener;
+    S.listen_udpv4 t.s ~port listener;
     S.listen t.s
 
   let serve_with_zonebufs t ~port ~zonebufs =
diff --git a/mirage/mdns_resolver_mirage.ml b/mirage/mdns_resolver_mirage.ml
index b3672e993..c98d82fcc 100644
--- a/mirage/mdns_resolver_mirage.ml
+++ b/mirage/mdns_resolver_mirage.ml
@@ -34,8 +34,7 @@ module Client : Dns.Protocol.CLIENT = struct
 
   let get_id () = 0
 
-  let marshal ?alloc q =
-    [q, DP.marshal (Dns.Buf.create ?alloc 4096) q]
+  let marshal ?alloc q = [q, DP.marshal ?alloc q]
 
   let packet_matches query packet =
     let open DP in
@@ -100,8 +99,7 @@ module Make(Time:Mirage_time_lwt.S)(S:Mirage_stack_lwt.V4) = struct
       (* FIXME: can't coexist with server yet because both listen on port 5353 *)
       S.listen_udpv4 s ~port:src_port callback;
       let rec txfn buf =
-        Cstruct.of_bigarray buf |>
-        S.UDPV4.write ~src_port ~dst ~dst_port udp >>= function
+        S.UDPV4.write ~src_port ~dst ~dst_port udp buf >>= function
         | Error e ->
           Fmt.kstrf fail_with
             "Attempting to communicate with remote resolver: %a"
@@ -111,7 +109,7 @@ module Make(Time:Mirage_time_lwt.S)(S:Mirage_stack_lwt.V4) = struct
       let rec rxfn f =
         Lwt_mvar.take mvar
         >>= fun buf ->
-        match f (Dns.Buf.of_cstruct buf) with
+        match f buf with
         | None -> rxfn f
         | Some packet -> return packet
       in
@@ -119,8 +117,6 @@ module Make(Time:Mirage_time_lwt.S)(S:Mirage_stack_lwt.V4) = struct
       Hashtbl.add res endp commfn;
       commfn
 
-  let alloc () = (Io_page.get 1 :> Dns.Buf.t)
-
   let create_packet q_class q_type q_name =
     let open Dns.Packet in
     let detail = {
@@ -138,7 +134,7 @@ module Make(Time:Mirage_time_lwt.S)(S:Mirage_stack_lwt.V4) = struct
       (q_name:Name.t) =
     let commfn = connect_to_resolver t (server,dns_port) in
     let q = create_packet q_class q_type q_name in
-    resolve_pkt ~alloc client commfn q
+    resolve_pkt client commfn q
 
   let gethostbyname
       t ?(server = default_ns) ?(dns_port = default_port)
diff --git a/opam b/opam
index dd23a75c4..ce1f70712 100644
--- a/opam
+++ b/opam
@@ -22,7 +22,7 @@ tags: [
 build: [
   ["ocaml" "pkg/pkg.ml" "build" "--pinned" "%{pinned}%" "--tests" "false"
     "--with-lwt" "%{lwt+mirage-profile+cmdliner:installed}%"
-    "--with-mirage" "%{mirage-time-lwt+mirage-stack-lwt+mirage-kv-lwt+lwt+duration+io-page+mirage-profile:installed}%"
+    "--with-mirage" "%{mirage-time-lwt+mirage-stack-lwt+mirage-kv-lwt+lwt+duration+mirage-profile:installed}%"
     "--with-async" "%{async:installed}%" ]
 ]
 build-test: [
@@ -53,7 +53,6 @@ depends: [
   "mirage-kv-lwt"    {test}
   "mirage-profile"   {test}
   "duration"         {test}
-  "io-page"          {test}
 ]
 depopts: [
   "async"
@@ -66,7 +65,6 @@ depopts: [
   "mirage-kv-lwt"
   "mirage-time-lwt"
   "duration"
-  "io-page"
 ]
 conflicts: [
   "mirage-types-lwt" {< "3.0.0"}