diff --git a/src/add-ons/kernel/network/datalink_protocols/arp/arp.cpp b/src/add-ons/kernel/network/datalink_protocols/arp/arp.cpp
index b8e9b6eadc..274d8c3c5e 100644
--- a/src/add-ons/kernel/network/datalink_protocols/arp/arp.cpp
+++ b/src/add-ons/kernel/network/datalink_protocols/arp/arp.cpp
@@ -258,9 +258,6 @@ ipv4_to_ether_multicast(sockaddr_dl *destination, const sockaddr_in *source)
 	//   the low-order 23 bits of the Ethernet multicast address
 	//   01-00-5E-00-00-00 (hex).''
 
-	memcpy(((uint8 *)destination->sdl_data) + 2, &source->sin_addr,
-		sizeof(in_addr));
-
 	destination->sdl_len = sizeof(sockaddr_dl);
 	destination->sdl_family = AF_DLI;
 	destination->sdl_index = 0;
@@ -269,7 +266,8 @@ ipv4_to_ether_multicast(sockaddr_dl *destination, const sockaddr_in *source)
 	destination->sdl_nlen = destination->sdl_slen = 0;
 	destination->sdl_alen = ETHER_ADDRESS_LENGTH;
 
-	uint32 *data = (uint32 *)destination->sdl_data;
+	memcpy(LLADDR(destination) + 2, &source->sin_addr, sizeof(in_addr));
+	uint32 *data = (uint32 *)LLADDR(destination);
 	data[0] = (data[0] & htonl(0x7f)) | htonl(0x01005e00);
 }
 
diff --git a/src/add-ons/kernel/network/datalink_protocols/ipv4_datagram/ipv4_datagram.cpp b/src/add-ons/kernel/network/datalink_protocols/ipv4_datagram/ipv4_datagram.cpp
index eee76dac2f..3f163ee3e4 100644
--- a/src/add-ons/kernel/network/datalink_protocols/ipv4_datagram/ipv4_datagram.cpp
+++ b/src/add-ons/kernel/network/datalink_protocols/ipv4_datagram/ipv4_datagram.cpp
@@ -97,6 +97,22 @@ ipv4_datalink_control(net_datalink_protocol *protocol, int32 op,
 }
 
 
+static status_t
+ipv4_datalink_join_multicast(net_datalink_protocol *protocol,
+	const sockaddr *address)
+{
+	return protocol->next->module->join_multicast(protocol->next, address);
+}
+
+
+static status_t
+ipv4_datalink_leave_multicast(net_datalink_protocol *protocol,
+	const sockaddr *address)
+{
+	return protocol->next->module->leave_multicast(protocol->next, address);
+}
+
+
 static status_t
 ipv4_datalink_std_ops(int32 op, ...)
 {
@@ -123,6 +139,8 @@ net_datalink_protocol_module_info gIPv4DataLinkModule = {
 	ipv4_datalink_up,
 	ipv4_datalink_down,
 	ipv4_datalink_control,
+	ipv4_datalink_join_multicast,
+	ipv4_datalink_leave_multicast,
 };
 
 module_info *modules[] = {
diff --git a/src/add-ons/kernel/network/devices/ethernet/ethernet.cpp b/src/add-ons/kernel/network/devices/ethernet/ethernet.cpp
index 3c1a99d4bb..f1d6b8d8c2 100644
--- a/src/add-ons/kernel/network/devices/ethernet/ethernet.cpp
+++ b/src/add-ons/kernel/network/devices/ethernet/ethernet.cpp
@@ -391,8 +391,7 @@ ethernet_add_multi(struct net_device *_device, const sockaddr *_address)
 	if (address->sdl_type != IFT_ETHER)
 		return EINVAL;
 
-	return ioctl(device->fd, ETHER_ADDMULTI, address->sdl_data,
-		address->sdl_alen);
+	return ioctl(device->fd, ETHER_ADDMULTI, LLADDR(address), 6);
 }
 
 
@@ -408,8 +407,7 @@ ethernet_rem_multi(struct net_device *_device, const sockaddr *_address)
 	if (address->sdl_type != IFT_ETHER)
 		return EINVAL;
 
-	return ioctl(device->fd, ETHER_REMMULTI, address->sdl_data,
-		address->sdl_alen);
+	return ioctl(device->fd, ETHER_REMMULTI, LLADDR(address), 6);
 }
 
 
diff --git a/src/add-ons/kernel/network/protocols/ipv4/ipv4.cpp b/src/add-ons/kernel/network/protocols/ipv4/ipv4.cpp
index dd19b910b1..58bc1c256c 100644
--- a/src/add-ons/kernel/network/protocols/ipv4/ipv4.cpp
+++ b/src/add-ons/kernel/network/protocols/ipv4/ipv4.cpp
@@ -706,20 +706,26 @@ raw_receive_data(net_buffer *buffer)
 }
 
 
+static sockaddr *
+fill_sockaddr_in(sockaddr_in *destination, const in_addr &source)
+{
+	memset(destination, 0, sizeof(sockaddr_in));
+	destination->sin_family = AF_INET;
+	destination->sin_addr = source;
+	return (sockaddr *)destination;
+}
+
+
 status_t
 IPv4Multicast::JoinGroup(IPv4GroupInterface *state)
 {
 	BenaphoreLocker _(sMulticastGroupsLock);
 
 	sockaddr_in groupAddr;
-	memset(&groupAddr, 0, sizeof(groupAddr));
-	groupAddr.sin_addr = state->Address();
-
 	net_interface *intf = state->Interface();
 
-	status_t status =
-		intf->first_protocol->module->join_multicast(intf->first_protocol,
-			(sockaddr *)&groupAddr);
+	status_t status = intf->first_info->join_multicast(intf->first_protocol,
+		fill_sockaddr_in(&groupAddr, state->Address()));
 	if (status < B_OK)
 		return status;
 
@@ -736,13 +742,10 @@ IPv4Multicast::LeaveGroup(IPv4GroupInterface *state)
 	sMulticastState->Remove(state);
 
 	sockaddr_in groupAddr;
-	memset(&groupAddr, 0, sizeof(groupAddr));
-	groupAddr.sin_addr = state->Address();
-
 	net_interface *intf = state->Interface();
 
 	return intf->first_protocol->module->join_multicast(intf->first_protocol,
-		(sockaddr *)&groupAddr);
+		fill_sockaddr_in(&groupAddr, state->Address()));
 }
 
 
@@ -913,14 +916,19 @@ ipv4_generic_delta_membership(ipv4_protocol *protocol, int option,
 	if (_sourceAddr && _sourceAddr->ss_family != AF_INET)
 		return EINVAL;
 
-	net_interface *interface = sDatalinkModule->get_interface(sDomain, index);
-	if (interface == NULL)
-		return ENODEV;
-
+	net_interface *interface;
 	const in_addr *groupAddr, *sourceAddr = NULL;
 
 	groupAddr = &((const sockaddr_in *)_groupAddr)->sin_addr;
 
+	if (index == 0)
+		interface = get_multicast_interface(protocol, groupAddr);
+	else
+		interface = sDatalinkModule->get_interface(sDomain, index);
+
+	if (interface == NULL)
+		return ENODEV;
+
 	if (_sourceAddr)
 		sourceAddr = &((const sockaddr_in *)_sourceAddr)->sin_addr;