diff --git a/src/core/ipv4/dhcp.c b/src/core/ipv4/dhcp.c
index 288b5585..ded63619 100644
--- a/src/core/ipv4/dhcp.c
+++ b/src/core/ipv4/dhcp.c
@@ -78,6 +78,7 @@
 #include "lwip/dns.h"
 #include "lwip/etharp.h"
 #include "lwip/prot/dhcp.h"
+#include "lwip/prot/iana.h"
 
 #include <string.h>
 
@@ -1908,7 +1909,7 @@ dhcp_create_msg(struct netif *netif, struct dhcp *dhcp, u8_t message_type, u16_t
 
   msg_out->op = DHCP_BOOTREQUEST;
   /* @todo: make link layer independent */
-  msg_out->htype = DHCP_HTYPE_ETH;
+  msg_out->htype = IANA_HWTYPE_ETHERNET;
   msg_out->hlen = netif->hwaddr_len;
   msg_out->xid = lwip_htonl(dhcp->xid);
   /* we don't need the broadcast flag since we can receive unicast traffic
diff --git a/src/core/ipv4/etharp.c b/src/core/ipv4/etharp.c
index d4c9928e..4a2d9a32 100644
--- a/src/core/ipv4/etharp.c
+++ b/src/core/ipv4/etharp.c
@@ -52,6 +52,7 @@
 #include "lwip/snmp.h"
 #include "lwip/dhcp.h"
 #include "lwip/autoip.h"
+#include "lwip/prot/iana.h"
 #include "netif/ethernet.h"
 
 #include <string.h>
@@ -650,7 +651,7 @@ etharp_input(struct pbuf *p, struct netif *netif)
   hdr = (struct etharp_hdr *)p->payload;
 
   /* RFC 826 "Packet Reception": */
-  if ((hdr->hwtype != PP_HTONS(HWTYPE_ETHERNET)) ||
+  if ((hdr->hwtype != PP_HTONS(IANA_HWTYPE_ETHERNET)) ||
       (hdr->hwlen != ETH_HWADDR_LEN) ||
       (hdr->protolen != sizeof(ip4_addr_t)) ||
       (hdr->proto != PP_HTONS(ETHTYPE_IP)))  {
@@ -1139,7 +1140,7 @@ etharp_raw(struct netif *netif, const struct eth_addr *ethsrc_addr,
   IPADDR_WORDALIGNED_COPY_FROM_IP4_ADDR_T(&hdr->sipaddr, ipsrc_addr);
   IPADDR_WORDALIGNED_COPY_FROM_IP4_ADDR_T(&hdr->dipaddr, ipdst_addr);
 
-  hdr->hwtype = PP_HTONS(HWTYPE_ETHERNET);
+  hdr->hwtype = PP_HTONS(IANA_HWTYPE_ETHERNET);
   hdr->proto = PP_HTONS(ETHTYPE_IP);
   /* set hwlen and protolen */
   hdr->hwlen = ETH_HWADDR_LEN;
diff --git a/src/include/lwip/prot/dhcp.h b/src/include/lwip/prot/dhcp.h
index 112953cb..2ac8907a 100644
--- a/src/include/lwip/prot/dhcp.h
+++ b/src/include/lwip/prot/dhcp.h
@@ -128,9 +128,6 @@ typedef enum {
 #define DHCP_RELEASE                7
 #define DHCP_INFORM                 8
 
-/** DHCP hardware type, currently only ethernet is supported */
-#define DHCP_HTYPE_ETH              1
-
 #define DHCP_MAGIC_COOKIE           0x63825363UL
 
 /* This is a list of options for BOOTP and DHCP, see RFC 2132 for descriptions */
diff --git a/src/include/lwip/prot/etharp.h b/src/include/lwip/prot/etharp.h
index 11a0810a..811c2284 100644
--- a/src/include/lwip/prot/etharp.h
+++ b/src/include/lwip/prot/etharp.h
@@ -101,12 +101,6 @@ PACK_STRUCT_END
 
 #define SIZEOF_ETHARP_HDR 28
 
-/* ARP hwtype values */
-enum etharp_hwtype {
-  HWTYPE_ETHERNET = 1
-  /* others not used */
-};
-
 /* ARP message types (opcodes) */
 enum etharp_opcode {
   ARP_REQUEST = 1,
diff --git a/src/include/lwip/prot/iana.h b/src/include/lwip/prot/iana.h
new file mode 100644
index 00000000..c4274875
--- /dev/null
+++ b/src/include/lwip/prot/iana.h
@@ -0,0 +1,51 @@
+/**
+ * @file
+ * IANA assigned numbers
+ */
+
+/*
+ * Copyright (c) 2017 Dirk Ziegelmeier.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Dirk Ziegelmeier <dziegel@gmx.de>
+ *
+ */
+
+#ifndef LWIP_HDR_PROT_IANA_H
+#define LWIP_HDR_PROT_IANA_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define IANA_HWTYPE_ETHERNET  1
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_HDR_PROT_IANA_H */
diff --git a/test/unit/etharp/test_etharp.c b/test/unit/etharp/test_etharp.c
index 67b02d0b..9b26edae 100644
--- a/test/unit/etharp/test_etharp.c
+++ b/test/unit/etharp/test_etharp.c
@@ -4,6 +4,7 @@
 #include "lwip/etharp.h"
 #include "netif/ethernet.h"
 #include "lwip/stats.h"
+#include "lwip/prot/iana.h"
 
 #if !LWIP_STATS || !UDP_STATS || !MEMP_STATS || !ETHARP_STATS
 #error "This tests needs UDP-, MEMP- and ETHARP-statistics enabled"
@@ -89,7 +90,7 @@ create_arp_response(ip4_addr_t *adr)
   ethhdr->src = test_ethaddr2;
   ethhdr->type = htons(ETHTYPE_ARP);
 
-  etharphdr->hwtype = htons(/*HWTYPE_ETHERNET*/ 1);
+  etharphdr->hwtype = htons(IANA_HWTYPE_ETHERNET);
   etharphdr->proto = htons(ETHTYPE_IP);
   etharphdr->hwlen = ETHARP_HWADDR_LEN;
   etharphdr->protolen = sizeof(ip4_addr_t);