diff --git a/simple-udp-service.rkt b/simple-udp-service.rkt
index f1a9619..aae6676 100644
--- a/simple-udp-service.rkt
+++ b/simple-udp-service.rkt
@@ -2,6 +2,7 @@
 
 ;; Simple imperative UDP server harness.
 
+(require racket/match)
 (require racket/udp)
 (require "dump-bytes.rkt")
 
@@ -21,8 +22,9 @@
 (define (start-udp-service
 	 port-number ;; Uint16
 	 packet-classifier ;; UdpPacket -> Maybe<ClassifiedPacket>
-	 bad-packet-handler ;; UdpPacket ServerState -> ListOf<UdpPacket> ServerState
-	 good-packet-handler ;; ClassifiedPacket ServerState -> ListOf<UdpPacket> ServerState
+	 bad-packet-handler ;; UdpPacket ServerState -> ListOf<ClassifiedPacket> ServerState
+	 good-packet-handler ;; ClassifiedPacket ServerState -> ListOf<ClassifiedPacket> ServerState
+	 packet-encoder ;; ClassifiedPacket -> UdpPacket
 	 initial-state ;; ServerState
 	 #:packet-size-limit
 	   [packet-size-limit 65536])
@@ -48,7 +50,8 @@
        (else (good-packet-handler classified-packet old-state))))
 
     (for-each (lambda (p)
-		(udp-send-to s (udp-packet-host p) (udp-packet-port p) (udp-packet-body p)))
+		(match-define (udp-packet body host port) (packet-encoder p))
+		(udp-send-to s host port body))
 	      reply-packets)
     new-state)
 
diff --git a/simplified-driver.rkt b/simplified-driver.rkt
index 4451299..d8c9b31 100644
--- a/simplified-driver.rkt
+++ b/simplified-driver.rkt
@@ -71,6 +71,7 @@
    classify-dns-packet
    (lambda (packet old-state) (values (log-error packet) old-state))
    (lambda (message old-state) (values (handle-request soa-rr zone message) old-state))
+   encode-dns-packet
    #f
    #:packet-size-limit 512))
 
@@ -79,6 +80,10 @@
   (with-handlers ((exn? (lambda (e) #f)))
     (list (packet->dns-message body) host port)))
 
+(define (encode-dns-packet data)
+  (match-define (list message host port) data)
+  (udp-packet (dns-message->packet message) host port))
+
 ;; UdpPacket -> ListOf<UdpPacket>
 (define (log-error packet)
   (pretty-print `(bad-packet-received ,packet))
@@ -159,9 +164,7 @@
   ;; TODO: check opcode and direction in request
   ;; TODO: think again about multiple questions in one packet
   (map (lambda (q)
-	 (udp-packet (dns-message->packet (answer-question q make-reply))
-		     request-host
-		     request-port))
+	 (list (answer-question q make-reply) request-host request-port))
        (dns-message-questions request-message)))
 
 (start-server 5555