diff --git a/src/rawnet/rawnetarch_darwin.c b/src/rawnet/rawnetarch_darwin.c
index 8855d46..dc362ab 100644
--- a/src/rawnet/rawnetarch_darwin.c
+++ b/src/rawnet/rawnetarch_darwin.c
@@ -20,6 +20,7 @@ static const uint8_t broadcast_mac[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
 static interface_ref interface;
 static uint8_t interface_mac[6];
+static uint8_t interface_fake_mac[6];
 static uint64_t interface_mtu;
 static uint64_t interface_packet_size;
 static vmnet_return_t interface_status;
@@ -49,6 +50,7 @@ int rawnet_arch_activate(const char *interface_name) {
 	 */
 
 	memset(interface_mac, 0, sizeof(interface_mac));
+	memset(interface_fake_mac, 0, sizeof(interface_fake_mac));
 	interface_status = 0;
 	interface_mtu = 0;
 	interface_packet_size = 0;
@@ -124,7 +126,11 @@ void rawnet_arch_deactivate(void) {
 }
 
 void rawnet_arch_set_mac(const uint8_t mac[6]) {
-	/* NOP */
+
+#ifdef RAWNET_DEBUG_ARCH
+    log_message( rawnet_arch_log, "New MAC address set: %02X:%02X:%02X:%02X:%02X:%02X.", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5] );
+#endif
+    memcpy(interface_fake_mac, mac, 6);
 }
 void rawnet_arch_set_hashfilter(const uint32_t hash_mask[2]) {
 	/* NOP */
@@ -138,12 +144,213 @@ void rawnet_arch_line_ctl(int bEnableTransmitter, int bEnableReceiver) {
 	/* NOP */
 }
 
+
+
+
+enum {
+	eth_dest	= 0,	// destination address
+	eth_src		= 6,	// source address
+	eth_type	= 12,	// packet type
+	eth_data	= 14,	// packet data
+};
+
+enum {
+	ip_ver_ihl	= 0,
+	ip_tos		= 1,
+	ip_len		= 2,
+	ip_id		= 4,
+	ip_frag		= 6,
+	ip_ttl		= 8,
+	ip_proto		= 9,
+	ip_header_cksum = 10,
+	ip_src		= 12,
+	ip_dest		= 16,
+	ip_data		= 20,
+};
+
+enum {
+	udp_source = 0, // source port
+	udp_dest = 2, // destination port
+	udp_len = 4, // length
+	udp_cksum = 6, // checksum
+	udp_data = 8, // total length udp header
+};
+
+enum {
+	bootp_op = 0, // operation
+	bootp_hw = 1, // hardware type
+	bootp_hlen = 2, // hardware len
+	bootp_hp = 3, // hops
+	bootp_transid = 4, // transaction id
+	bootp_secs = 8, // seconds since start
+	bootp_flags = 10, // flags
+	bootp_ipaddr = 12, // ip address knwon by client
+	bootp_ipclient = 16, // client ip from server
+	bootp_ipserver = 20, // server ip
+	bootp_ipgateway = 24, // gateway ip
+	bootp_client_hrd = 28, // client mac address
+	bootp_spare = 34,
+	bootp_host = 44,
+	bootp_fname = 108,
+	bootp_data = 236, // total length bootp packet
+};
+
+enum {
+	arp_hw = 14,		// hw type (eth = 0001)
+	arp_proto = 16,		// protocol (ip = 0800)
+	arp_hwlen = 18,		// hw addr len (eth = 06)
+	arp_protolen = 19,	// proto addr len (ip = 04)
+	arp_op = 20,		// request = 0001, reply = 0002
+	arp_shw = 22,		// sender hw addr
+	arp_sp = 28,		// sender proto addr
+	arp_thw = 32,		// target hw addr
+	arp_tp = 38,		// target protoaddr
+	arp_data = 42,	// total length of packet
+};
+
+enum {
+	dhcp_discover = 1,
+	dhcp_offer = 2,
+	dhcp_request = 3,
+	dhcp_decline = 4,
+	dhcp_pack = 5,
+	dhcp_nack = 6,
+	dhcp_release = 7,
+	dhcp_inform = 8,
+};
+
+static uint8_t oo[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+static uint8_t ff[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+
+static int is_arp(const uint8_t *packet, unsigned size) {
+	return size == arp_data
+		&& packet[12] == 0x08 && packet[13] == 0x06 /* ARP */
+		&& packet[14] == 0x00 && packet[15] == 0x01 /* ethernet */
+		&& packet[16] == 0x08 && packet[17] == 0x00 /* ipv4 */
+		&& packet[18] == 0x06 /* hardware size */
+		&& packet[19] == 0x04 /* protocol size */
+	;
+}
+
+static int is_broadcast(const uint8_t *packet, unsigned size) {
+	return !memcmp(packet + 0, ff, 6);
+}
+
+static int is_unicast(const uint8_t *packet, unsigned size) {
+	return (*packet & 0x01) == 0;
+}
+
+static int is_multicast(const uint8_t *packet, unsigned size) {
+	return (*packet & 0x01) == 0x01 && !is_broadcast(packet, size);
+}
+
+static int is_dhcp_out(const uint8_t *packet, unsigned size) {
+	static uint8_t cookie[] = { 0x63, 0x82, 0x53, 0x63 };
+	return size >= 282
+		//&& !memcmp(&packet[0], ff, 6) /* broadcast */
+		&& packet[12] == 0x08 && packet[13] == 0x00
+		&& packet[14] == 0x45 /* version 4 */
+		&& packet[23] == 0x11 /* UDP */
+		//&& !memcmp(&packet[26], oo, 4)  /* source ip */
+		//&& !memcmp(&packet[30], ff, 4)  /* dest ip */
+		&& packet[34] == 0x00 && packet[35] == 0x44 /* source port */
+		&& packet[36] == 0x00 && packet[37] == 0x43 /* dest port */
+		//&& packet[44] == 0x01 /* dhcp boot req */
+		&& packet[43] == 0x01 /* ethernet */
+		&& packet[44] == 0x06 /* 6 byte mac */
+		&& !memcmp(&packet[278], cookie, 4)
+	;
+}
+
+
+static int is_dhcp_in(const uint8_t *packet, unsigned size) {
+	static uint8_t cookie[] = { 0x63, 0x82, 0x53, 0x63 };
+	return size >= 282
+		//&& !memcmp(&packet[0], ff, 6) /* broadcast */
+		&& packet[12] == 0x08 && packet[13] == 0x00
+		&& packet[14] == 0x45 /* version 4 */
+		&& packet[23] == 0x11 /* UDP */
+		//&& !memcmp(&packet[26], oo, 4)  /* source ip */
+		//&& !memcmp(&packet[30], ff, 4)  /* dest ip */
+		&& packet[34] == 0x00 && packet[35] == 0x43 /* source port */
+		&& packet[36] == 0x00 && packet[37] == 0x44 /* dest port */
+		//&& packet[44] == 0x01 /* dhcp boot req */
+		&& packet[43] == 0x01 /* ethernet */
+		&& packet[44] == 0x06 /* 6 byte mac */
+		&& !memcmp(&packet[278], cookie, 4)
+	;
+}
+
+static unsigned ip_checksum(const uint8_t *packet) {
+	unsigned x = 0;
+	unsigned i;
+	for (i = 0; i < ip_data; i += 2) {
+		if (i == ip_header_cksum) continue;
+		x += packet[eth_data + i + 0 ] << 8;
+		x += packet[eth_data + i + 1];
+	}
+
+	/* add the carry */
+	x += x >> 16;
+	x &= 0xffff;
+	return ~x & 0xffff;
+}
+
+static void fix_incoming_packet(uint8_t *packet, unsigned size, const uint8_t real_mac[6], const uint8_t fake_mac[6]) {
+
+	if (memcmp(packet + 0, real_mac, 6) == 0)
+		memcpy(packet + 0, fake_mac, 6);
+
+	/* dhcp request - fix the hardware address */
+	if (is_unicast(packet, size) && is_dhcp_in(packet, size)) {
+		if (!memcmp(packet + 70, real_mac, 6))
+			memcpy(packet + 70, fake_mac, 6);
+		return;
+	}
+
+}
+
+static void fix_outgoing_packet(uint8_t *packet, unsigned size, const uint8_t real_mac[6], const uint8_t fake_mac[6]) {
+
+
+
+	if (memcmp(packet + 6, fake_mac, 6) == 0)
+		memcpy(packet + 6, real_mac, 6);
+
+	if (is_arp(packet, size)) {
+		/* sender mac address */
+		if (!memcmp(packet + 22, fake_mac, 6))
+			memcpy(packet + 22, real_mac, 6);
+		return;
+	}
+
+	/* dhcp request - fix the hardware address */
+	if (is_broadcast(packet, size) && is_dhcp_out(packet, size)) {
+		/* set source ip to 0 - LL bug? */
+		/* fixed in link layer as of 2018-12-17 */
+#if 0
+		unsigned ck;
+		memset(packet + 26, 0, 4);
+		ck = ip_checksum(packet);
+		packet[eth_data + ip_header_cksum + 0] = ck >> 8;
+		packet[eth_data + ip_header_cksum + 1] = ck;
+#endif
+
+		if (!memcmp(packet + 70, fake_mac, 6))
+			memcpy(packet + 70, real_mac, 6);
+		return;
+	}
+
+}
+
+
 void rawnet_arch_transmit(int force, int onecoll, int inhibit_crc, int tx_pad_dis, int txlength, uint8_t *txframe) {
 
 	int count = 1;
 	vmnet_return_t st;
 	struct vmpktdesc v;
 	struct iovec iov;
+	uint8_t *buffer;
 
 	if (txlength == 0) return;
 	if (txlength > interface_packet_size) {
@@ -151,8 +358,17 @@ void rawnet_arch_transmit(int force, int onecoll, int inhibit_crc, int tx_pad_di
 		return;
 	}
 
+	if (txlength < 12) {
+		log_message(rawnet_arch_log, "packet is too small: %d", txlength);
+		return;
+	}
 
-	iov.iov_base = txframe;
+	/* copy the buffer and fix the source mac address. */
+	buffer = (uint8_t *)calloc(txlength, 1);
+	memcpy(buffer, txframe, txlength);
+	fix_outgoing_packet(buffer, txlength, interface_mac, interface_fake_mac);
+
+	iov.iov_base = buffer;
 	iov.iov_len = txlength;
 
 	v.vm_pkt_size = txlength;
@@ -161,11 +377,12 @@ void rawnet_arch_transmit(int force, int onecoll, int inhibit_crc, int tx_pad_di
 	v.vm_flags = 0;
 
 
-	fprintf(stderr, "\rawnet_arch_transmit: %u\n", (unsigned)iov.iov_len);
-	rawnet_hexdump(iov.iov_base, iov.iov_len);
+	fprintf(stderr, "\nrawnet_arch_transmit: %u\n", (unsigned)iov.iov_len);
+	rawnet_hexdump(buffer, v.vm_pkt_size);
 
 	
 	st = vmnet_write(interface, &v, &count);
+	free(buffer);
 	if (st != VMNET_SUCCESS) {
 		log_message(rawnet_arch_log, "vmnet_write failed!");
 	}
@@ -174,7 +391,7 @@ void rawnet_arch_transmit(int force, int onecoll, int inhibit_crc, int tx_pad_di
 
 int rawnet_arch_receive(uint8_t *pbuffer, int *plen, int *phashed, int *phash_index, int *prx_ok, int *pcorrect_mac, int *pbroadcast, int *pcrc_error) {
 
-	char *buffer;
+	uint8_t *buffer;
 	//unsigned hashreg;
 
 	int count = 1;
@@ -184,7 +401,7 @@ int rawnet_arch_receive(uint8_t *pbuffer, int *plen, int *phashed, int *phash_in
 	struct iovec iov;
 
 
-	buffer = calloc(interface_packet_size, 1);
+	buffer = (uint8_t *)calloc(interface_packet_size, 1);
 
 	iov.iov_base = buffer;
 	iov.iov_len = interface_packet_size;
@@ -206,9 +423,13 @@ int rawnet_arch_receive(uint8_t *pbuffer, int *plen, int *phashed, int *phash_in
 		return 0;
 	}
 
+	fix_incoming_packet(buffer, v.vm_pkt_size, interface_mac, interface_fake_mac);
+
 	// iov.iov_len is not updated with the read count, apparently. 
-	fprintf(stderr, "\nrawnet_arch_receive: %u\n", (unsigned)v.vm_pkt_size);
-	rawnet_hexdump(iov.iov_base, v.vm_pkt_size);
+	if (!is_multicast(buffer, v.vm_pkt_size)) { /* multicast crap */
+		fprintf(stderr, "\nrawnet_arch_receive: %u\n", (unsigned)v.vm_pkt_size);
+		rawnet_hexdump(buffer, v.vm_pkt_size);
+	}
 
 	xfer = v.vm_pkt_size;
 	if (xfer > *plen) xfer = *plen;
@@ -225,9 +446,11 @@ int rawnet_arch_receive(uint8_t *pbuffer, int *plen, int *phashed, int *phash_in
 	*pcrc_error = 0;
 
 	*prx_ok = 1;
+	#if 0
 	*pcorrect_mac = memcmp(buffer, interface_mac, 6) == 0;
 	*pbroadcast = memcmp(buffer, broadcast_mac, 6) == 0;
-	
+	#endif
+
 	/* vmnet won't send promiscuous packets */
 	#if 0
 	hashreg = (~crc32_buf(buffer, 6) >> 26) & 0x3f;