diff --git a/ipacm/inc/IPACM_Config.h b/ipacm/inc/IPACM_Config.h
index 9230f7d..2792f62 100644
--- a/ipacm/inc/IPACM_Config.h
+++ b/ipacm/inc/IPACM_Config.h
@@ -94,7 +94,7 @@
 	ipacm_alg *alg_table;
 
 	/* Store private subnet configuration from XML file */
-	ipa_private_subnet private_subnet_table[IPA_MAX_PRIVATE_SUBNET_ENTRIES];
+	ipa_private_subnet private_subnet_table[IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES];
 
 	/* Store the non nat iface names */
 	NatIfaces *pNatIfaces;
diff --git a/ipacm/inc/IPACM_Defs.h b/ipacm/inc/IPACM_Defs.h
index 65d5ce4..b1daf35 100644
--- a/ipacm/inc/IPACM_Defs.h
+++ b/ipacm/inc/IPACM_Defs.h
@@ -77,6 +77,7 @@
 
 #define IPA_MAX_IFACE_ENTRIES 20
 #define IPA_MAX_PRIVATE_SUBNET_ENTRIES 3
+#define IPA_MAX_MTU_ENTRIES 3
 #define IPA_MAX_ALG_ENTRIES 20
 #define IPA_MAX_RM_ENTRY 6
 
@@ -106,6 +107,7 @@
 #define TCP_SYN_SHIFT 17
 #define TCP_RST_SHIFT 18
 #define NUM_IPV6_PREFIX_FLT_RULE 1
+#define NUM_IPV6_PREFIX_MTU_RULE 1
 
 /*---------------------------------------------------------------------------
 										Return values indicating error status
@@ -124,6 +126,7 @@
 #define IPA_MAC_ADDR_SIZE  6
 #define IPA_MAX_NUM_SW_PDNS 15
 
+#define DEFAULT_MTU_SIZE 1500
 /*===========================================================================
 										 GLOBAL DEFINITIONS AND DECLARATIONS
 ===========================================================================*/
diff --git a/ipacm/inc/IPACM_Lan.h b/ipacm/inc/IPACM_Lan.h
index bf815c5..605edb5 100644
--- a/ipacm/inc/IPACM_Lan.h
+++ b/ipacm/inc/IPACM_Lan.h
@@ -113,7 +113,7 @@
 	uint32_t lan_wan_fl_rule_hdl[IPA_WAN_DEFAULT_FILTER_RULE_HANDLES];
 
 	/* store private-subnet filter rule handlers */
-	uint32_t private_fl_rule_hdl[IPA_MAX_PRIVATE_SUBNET_ENTRIES];
+	uint32_t private_fl_rule_hdl[IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES];
 
 	/* LAN-iface's callback function */
 	void event_callback(ipa_cm_event_id event, void *data);
@@ -258,7 +258,7 @@
 
 	uint32_t ipv4_icmp_flt_rule_hdl[NUM_IPV4_ICMP_FLT_RULE];
 
-	uint32_t ipv6_prefix_flt_rule_hdl[NUM_IPV6_PREFIX_FLT_RULE];
+	uint32_t ipv6_prefix_flt_rule_hdl[NUM_IPV6_PREFIX_FLT_RULE + NUM_IPV6_PREFIX_MTU_RULE];
 	uint32_t ipv6_icmp_flt_rule_hdl[NUM_IPV6_ICMP_FLT_RULE];
 
 	int num_wan_ul_fl_rule_v4;
@@ -464,6 +464,8 @@
 	/* for pcie modem */
 	virtual int add_connection(int client_index, int v6_num);
 	virtual int del_connection(int client_index, int v6_num);
+
+	int construct_mtu_rule(struct ipa_flt_rule *rule, enum ipa_ip_type iptype, uint16_t mtu);
 };
 
 #endif /* IPACM_LAN_H */
diff --git a/ipacm/inc/IPACM_Wan.h b/ipacm/inc/IPACM_Wan.h
index 684bfb7..31949c5 100644
--- a/ipacm/inc/IPACM_Wan.h
+++ b/ipacm/inc/IPACM_Wan.h
@@ -105,6 +105,8 @@
 	static bool wan_up;
 	static bool wan_up_v6;
 	static uint8_t xlat_mux_id;
+	static uint16_t mtu_default_wan;
+	uint16_t mtu_size;
 	/* IPACM interface name */
 	static char wan_up_dev_name[IF_NAME_LEN];
 	static uint32_t curr_wan_ip;
@@ -137,6 +139,26 @@
 #endif
 	}
 
+	static uint16_t queryMTU(int ipa_if_num_tether, enum ipa_ip_type iptype)
+	{
+		if (iptype == IPA_IP_v4)
+		{
+			if (isWanUP(ipa_if_num_tether))
+			{
+				return mtu_default_wan;
+			}
+		}
+		else if (iptype == IPA_IP_v6)
+		{
+			if (isWanUP_V6(ipa_if_num_tether))
+			{
+				return mtu_default_wan;
+
+			}
+		}
+		return DEFAULT_MTU_SIZE;
+	}
+
 	static bool isWanUP_V6(int ipa_if_num_tether)
 	{
 #ifdef FEATURE_IPA_ANDROID
@@ -653,6 +675,9 @@
 	int add_tcp_fin_rst_exception_rule();
 
 	int delete_tcp_fin_rst_exception_rule();
+
+	/* Query mtu size */
+	int query_mtu_size();
 };
 
 #endif /* IPACM_WAN_H */
diff --git a/ipacm/src/IPACM_Iface.cpp b/ipacm/src/IPACM_Iface.cpp
index ec4a9ea..efa941c 100644
--- a/ipacm/src/IPACM_Iface.cpp
+++ b/ipacm/src/IPACM_Iface.cpp
@@ -938,15 +938,12 @@
 		memcpy(&(m_pFilteringTable->rules[3]), &flt_rule_entry, sizeof(struct ipa_flt_rule_add));
 
 #ifdef FEATURE_IPA_ANDROID
-		/* Add the ipv6 tcp fragment filtering rule. */
+		/* Add the ipv6 tcp/udp fragment filtering rule for MTU */
 
-		IPACMDBG_H("Adding IPv6 TCP fragment filter rule\n");
+		IPACMDBG_H("Adding IPv6 fragment filter rule\n");
 
 		flt_rule_entry.rule.attrib.attrib_mask &= ~((uint32_t)IPA_FLT_DST_ADDR);
 
-		flt_rule_entry.rule.attrib.attrib_mask |= IPA_FLT_NEXT_HDR;
-		flt_rule_entry.rule.attrib.u.v6.next_hdr = IPACM_FIREWALL_IPPROTO_TCP;
-
 		flt_rule_entry.rule.attrib.attrib_mask |= IPA_FLT_FRAGMENT;
 
 		memcpy(&(m_pFilteringTable->rules[4]), &flt_rule_entry,
diff --git a/ipacm/src/IPACM_Lan.cpp b/ipacm/src/IPACM_Lan.cpp
index 755d730..41c3723 100644
--- a/ipacm/src/IPACM_Lan.cpp
+++ b/ipacm/src/IPACM_Lan.cpp
@@ -129,8 +129,8 @@
 
 	memset(ipv4_icmp_flt_rule_hdl, 0, NUM_IPV4_ICMP_FLT_RULE * sizeof(uint32_t));
 
-	memset(private_fl_rule_hdl, 0, IPA_MAX_PRIVATE_SUBNET_ENTRIES * sizeof(uint32_t));
-	memset(ipv6_prefix_flt_rule_hdl, 0, NUM_IPV6_PREFIX_FLT_RULE * sizeof(uint32_t));
+	memset(private_fl_rule_hdl, 0, (IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES) * sizeof(uint32_t));
+	memset(ipv6_prefix_flt_rule_hdl, 0, (NUM_IPV6_PREFIX_FLT_RULE + NUM_IPV6_PREFIX_MTU_RULE) * sizeof(uint32_t));
 	memset(ipv6_icmp_flt_rule_hdl, 0, NUM_IPV6_ICMP_FLT_RULE * sizeof(uint32_t));
 	memset(ipv6_prefix, 0, sizeof(ipv6_prefix));
 
@@ -881,6 +881,11 @@
 		{
 			memcpy(ipv6_prefix, data_wan->ipv6_prefix, sizeof(ipv6_prefix));
 			install_ipv6_prefix_flt_rule(data_wan->ipv6_prefix);
+
+			/* MTU might have changed. Need to update ipv4 MTU rule if up */
+			if (IPACM_Wan::isWanUP(ipa_if_num))
+				handle_private_subnet_android(IPA_IP_v4);
+
 			if (data_wan->backhaul_type == Q6_WAN)
 			{
 				ext_prop = IPACM_Iface::ipacmcfg->GetExtProp(IPA_IP_v6);
@@ -1306,6 +1311,9 @@
 		sta_ul_v4_set = false;
 	}
 
+	/* clean MTU rules if needed */
+	handle_private_subnet_android(IPA_IP_v4);
+
 	close(fd);
 	return IPACM_SUCCESS;
 }
@@ -1644,6 +1652,18 @@
 
 	if(ip_type == IPA_IP_v4)
 	{
+		/* add MTU rules for ipv4 */
+		handle_private_subnet_android(IPA_IP_v4);
+
+		/* Update ipv6 MTU here if WAN_v6 is up and filter rules were installed */
+		if (IPACM_Wan::isWanUP_V6(ipa_if_num))
+		{
+			if (ipv6_prefix_flt_rule_hdl[0] && ipv6_prefix_flt_rule_hdl[1] ) {
+				delete_ipv6_prefix_flt_rule();
+				install_ipv6_prefix_flt_rule(IPACM_Wan::backhaul_ipv6_prefix);
+			}
+		}
+
 		if(sta_ul_v4_set == true)
 		{
 			IPACMDBG_H("Filetring rule for IPV4 of STA mode is already configured, sta_ul_v4_set: %d\n",sta_ul_v4_set);
@@ -1886,6 +1906,18 @@
 		ret = handle_uplink_filter_rule(ext_prop, iptype, xlat_mux_id);
 		modem_ul_v6_set = true;
 	} else if (iptype ==IPA_IP_v4 && modem_ul_v4_set == false) {
+		/* add MTU rules for ipv4 */
+		handle_private_subnet_android(IPA_IP_v4);
+
+		/* Update ipv6 MTU here if WAN_v6 is up and filter rules were installed */
+		if (IPACM_Wan::isWanUP_V6(ipa_if_num))
+		{
+			if (ipv6_prefix_flt_rule_hdl[0] && ipv6_prefix_flt_rule_hdl[1] ) {
+				delete_ipv6_prefix_flt_rule();
+				install_ipv6_prefix_flt_rule(IPACM_Wan::backhaul_ipv6_prefix);
+			}
+		}
+
 		IPACMDBG_H("check getXlat_Mux_Id:%d\n", IPACM_Wan::getXlat_Mux_Id());
 		IPACMDBG_H("IPA_IP_v4 xlat_mux_id: %d, modem_ul_v4_set %d\n", xlat_mux_id, modem_ul_v4_set);
 		ret = handle_uplink_filter_rule(ext_prop, iptype, xlat_mux_id);
@@ -3059,13 +3091,13 @@
 		}
 
 #ifdef FEATURE_IPA_ANDROID
-		if(m_filtering.DeleteFilteringHdls(private_fl_rule_hdl, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES) == false)
+		if(m_filtering.DeleteFilteringHdls(private_fl_rule_hdl, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES) == false)
 		{
 			IPACMERR("Error deleting private subnet IPv4 flt rules.\n");
 			res = IPACM_FAILURE;
 			goto fail;
 		}
-		IPACM_Iface::ipacmcfg->decreaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES);
+		IPACM_Iface::ipacmcfg->decreaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES);
 #else
 		if (m_filtering.DeleteFilteringHdls(private_fl_rule_hdl, IPA_IP_v4, IPACM_Iface::ipacmcfg->ipa_num_private_subnet) == false)
 		{
@@ -4044,7 +4076,7 @@
 	ipa_ioc_add_flt_rule* pFilteringTable;
 	bool result;
 
-	len = sizeof(struct ipa_ioc_add_flt_rule) +	IPA_MAX_PRIVATE_SUBNET_ENTRIES * sizeof(struct ipa_flt_rule_add);
+	len = sizeof(struct ipa_ioc_add_flt_rule) + (IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES) * sizeof(struct ipa_flt_rule_add);
 
 	pFilteringTable = (struct ipa_ioc_add_flt_rule *)malloc(len);
 	if (pFilteringTable == NULL)
@@ -4058,7 +4090,7 @@
 	pFilteringTable->ep = rx_prop->rx[0].src_pipe;
 	pFilteringTable->global = false;
 	pFilteringTable->ip = iptype;
-	pFilteringTable->num_rules = IPA_MAX_PRIVATE_SUBNET_ENTRIES;
+	pFilteringTable->num_rules = IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES;
 
 	memset(&flt_rule, 0, sizeof(struct ipa_flt_rule_add));
 
@@ -4081,7 +4113,7 @@
 		flt_rule.rule.attrib.u.v4.dst_addr_mask = ~0;
 		flt_rule.rule.attrib.u.v4.dst_addr = ~0;
 
-		for(i=0; i<IPA_MAX_PRIVATE_SUBNET_ENTRIES; i++)
+		for(i=0; i<IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES; i++)
 		{
 			memcpy(&(pFilteringTable->rules[i]), &flt_rule, sizeof(struct ipa_flt_rule_add));
 		}
@@ -4107,9 +4139,9 @@
 		}
 		else
 		{
-			IPACM_Iface::ipacmcfg->increaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES);
+			IPACM_Iface::ipacmcfg->increaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES);
 			/* copy filter rule hdls */
-			for (int i = 0; i < IPA_MAX_PRIVATE_SUBNET_ENTRIES; i++)
+			for (int i = 0; i < IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES; i++)
 			{
 				if (pFilteringTable->rules[i].status == 0)
 				{
@@ -4135,6 +4167,9 @@
 	int i, len, res = IPACM_SUCCESS;
 	struct ipa_flt_rule_mdfy flt_rule;
 	struct ipa_ioc_mdfy_flt_rule* pFilteringTable;
+	int mtu_rule_cnt = 0;
+	uint16_t mtu[IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES] = { };
+	int mtu_rule_idx = IPACM_Iface::ipacmcfg->ipa_num_private_subnet;
 
 	if (rx_prop == NULL)
 	{
@@ -4149,12 +4184,24 @@
 	}
 	else
 	{
-		for(i=0; i<IPA_MAX_PRIVATE_SUBNET_ENTRIES; i++)
+		for(i=0; i<IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES; i++)
 		{
 			reset_to_dummy_flt_rule(IPA_IP_v4, private_fl_rule_hdl[i]);
 		}
 
-		len = sizeof(struct ipa_ioc_mdfy_flt_rule) + (IPACM_Iface::ipacmcfg->ipa_num_private_subnet) * sizeof(struct ipa_flt_rule_mdfy);
+		/* check how many MTU rules we need to add */
+		for(i = 0; i < IPACM_Iface::ipacmcfg->ipa_num_private_subnet; i++)
+		{
+			mtu[i] = IPACM_Wan::queryMTU(ipa_if_num, IPA_IP_v4);
+
+			if (mtu[i] > 0)
+				mtu_rule_cnt++;
+			else
+				IPACMERR("MTU is zero\n");
+		}
+		IPACMDBG_H("total %d MTU rules are needed\n", mtu_rule_cnt);
+
+		len = sizeof(struct ipa_ioc_mdfy_flt_rule) + (IPACM_Iface::ipacmcfg->ipa_num_private_subnet + mtu_rule_cnt) * sizeof(struct ipa_flt_rule_mdfy);
 		pFilteringTable = (struct ipa_ioc_mdfy_flt_rule*)malloc(len);
 		if (!pFilteringTable)
 		{
@@ -4165,7 +4212,7 @@
 
 		pFilteringTable->commit = 1;
 		pFilteringTable->ip = iptype;
-		pFilteringTable->num_rules = (uint8_t)IPACM_Iface::ipacmcfg->ipa_num_private_subnet;
+		pFilteringTable->num_rules = (uint8_t)IPACM_Iface::ipacmcfg->ipa_num_private_subnet + mtu_rule_cnt;
 
 		/* Make LAN-traffic always go A5, use default IPA-RT table */
 		if (false == m_routing.GetRoutingTable(&IPACM_Iface::ipacmcfg->rt_tbl_default_v4))
@@ -4185,16 +4232,32 @@
 		flt_rule.rule.rt_tbl_hdl = IPACM_Iface::ipacmcfg->rt_tbl_default_v4.hdl;
 		IPACMDBG_H("Private filter rule use table: %s\n",IPACM_Iface::ipacmcfg->rt_tbl_default_v4.name);
 
-		memcpy(&flt_rule.rule.attrib, &rx_prop->rx[0].attrib, sizeof(flt_rule.rule.attrib));
-		flt_rule.rule.attrib.attrib_mask |= IPA_FLT_DST_ADDR;
-
 		for (i = 0; i < (IPACM_Iface::ipacmcfg->ipa_num_private_subnet); i++)
 		{
+			/* add private subnet rule for ipv4 */
+			flt_rule.rule.action = IPA_PASS_TO_ROUTING;
+			flt_rule.rule.eq_attrib_type = 0;
 			flt_rule.rule_hdl = private_fl_rule_hdl[i];
+			memcpy(&flt_rule.rule.attrib, &rx_prop->rx[0].attrib, sizeof(flt_rule.rule.attrib));
+			flt_rule.rule.attrib.attrib_mask |= IPA_FLT_DST_ADDR;
 			flt_rule.rule.attrib.u.v4.dst_addr_mask = IPACM_Iface::ipacmcfg->private_subnet_table[i].subnet_mask;
 			flt_rule.rule.attrib.u.v4.dst_addr = IPACM_Iface::ipacmcfg->private_subnet_table[i].subnet_addr;
 			memcpy(&(pFilteringTable->rules[i]), &flt_rule, sizeof(struct ipa_flt_rule_mdfy));
 			IPACMDBG_H(" IPACM private subnet_addr as: 0x%x entry(%d)\n", flt_rule.rule.attrib.u.v4.dst_addr, i);
+
+			/* add corresponding MTU rule for ipv4 */
+			if (mtu[i] > 0)
+			{
+				flt_rule.rule_hdl = private_fl_rule_hdl[mtu_rule_idx + i];
+				memcpy(&flt_rule.rule.attrib, &rx_prop->rx[0].attrib, sizeof(flt_rule.rule.attrib));
+				flt_rule.rule.attrib.u.v4.src_addr_mask = IPACM_Iface::ipacmcfg->private_subnet_table[i].subnet_mask;
+				flt_rule.rule.attrib.u.v4.src_addr = IPACM_Iface::ipacmcfg->private_subnet_table[i].subnet_addr;
+				flt_rule.rule.attrib.attrib_mask |= IPA_FLT_SRC_ADDR;
+				if (construct_mtu_rule(&flt_rule.rule, IPA_IP_v4, mtu[i]))
+					IPACMERR("Failed to modify MTU filtering rule.\n");
+				memcpy(&(pFilteringTable->rules[mtu_rule_idx + i]), &flt_rule, sizeof(struct ipa_flt_rule_mdfy));
+				IPACMDBG_H("Adding MTU rule for private subnet 0x%x.\n", flt_rule.rule.attrib.u.v4.src_addr);
+			}
 		}
 
 		if (false == m_filtering.ModifyFilteringRule(pFilteringTable))
@@ -4225,12 +4288,17 @@
 	struct ipa_ioc_add_flt_rule* flt_rule;
 	struct ipa_flt_rule_add flt_rule_entry;
 	bool result;
+	int rule_cnt = 1;
+
+	uint16_t mtu = IPACM_Wan::queryMTU(ipa_if_num, IPA_IP_v6);
+	if (mtu > 0)
+		rule_cnt ++;
 
 	if(rx_prop != NULL)
 	{
-		len = sizeof(struct ipa_ioc_add_flt_rule) + sizeof(struct ipa_flt_rule_add);
+		len = sizeof(struct ipa_ioc_add_flt_rule) + rule_cnt * sizeof(struct ipa_flt_rule_add);
 
-		flt_rule = (struct ipa_ioc_add_flt_rule *)calloc(1, len);
+		flt_rule = (struct ipa_ioc_add_flt_rule *)calloc(rule_cnt, len);
 		if (!flt_rule)
 		{
 			IPACMERR("Error Locate ipa_flt_rule_add memory...\n");
@@ -4241,7 +4309,7 @@
 		flt_rule->ep = rx_prop->rx[0].src_pipe;
 		flt_rule->global = false;
 		flt_rule->ip = IPA_IP_v6;
-		flt_rule->num_rules = 1;
+		flt_rule->num_rules = rule_cnt;
 
 		memset(&flt_rule_entry, 0, sizeof(struct ipa_flt_rule_add));
 
@@ -4267,6 +4335,30 @@
 		flt_rule_entry.rule.attrib.u.v6.dst_addr_mask[3] = 0x0;
 		memcpy(&(flt_rule->rules[0]), &flt_rule_entry, sizeof(struct ipa_flt_rule_add));
 
+		memcpy(&flt_rule_entry.rule.attrib, &rx_prop->rx[0].attrib, sizeof(flt_rule_entry.rule.attrib)); // this will remove the IPA_FLT_DST_ADDR
+		flt_rule_entry.rule.attrib.u.v6.src_addr[3] = prefix[0];
+		flt_rule_entry.rule.attrib.u.v6.src_addr[2] = prefix[1];
+		flt_rule_entry.rule.attrib.u.v6.src_addr[1] = 0x0;
+		flt_rule_entry.rule.attrib.u.v6.src_addr[0] = 0x0;
+		flt_rule_entry.rule.attrib.u.v6.src_addr_mask[3] = 0xFFFFFFFF;
+		flt_rule_entry.rule.attrib.u.v6.src_addr_mask[2] = 0xFFFFFFFF;
+		flt_rule_entry.rule.attrib.u.v6.src_addr_mask[1] = 0x0;
+		flt_rule_entry.rule.attrib.u.v6.src_addr_mask[0] = 0x0;
+		flt_rule_entry.rule.attrib.attrib_mask |= IPA_FLT_SRC_ADDR;
+
+		/* Add an MTU rule with every new private prefix */
+		if (mtu > 0)
+		{
+			if (construct_mtu_rule(&flt_rule_entry.rule, IPA_IP_v6, mtu))
+			{
+				IPACMERR("Failed to add MTU filtering rule.\n")
+			}
+			else
+			{
+				memcpy(&(flt_rule->rules[1]), &flt_rule_entry, sizeof(struct ipa_flt_rule_add));
+			}
+		}
+
 #ifdef IPA_IOCTL_SET_FNR_COUNTER_INFO
 		/* use index hw-counter */
 		if(ipa_if_cate == WLAN_IF && IPACM_Iface::ipacmcfg->hw_fnr_stats_support)
@@ -4288,9 +4380,14 @@
 		}
 		else
 		{
-			IPACM_Iface::ipacmcfg->increaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v6, 1);
+			IPACM_Iface::ipacmcfg->increaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v6, 2);
 			ipv6_prefix_flt_rule_hdl[0] = flt_rule->rules[0].flt_rule_hdl;
 			IPACMDBG_H("IPv6 prefix filter rule HDL:0x%x\n", ipv6_prefix_flt_rule_hdl[0]);
+			if (rule_cnt > 1)
+			{
+				ipv6_prefix_flt_rule_hdl[1] = flt_rule->rules[1].flt_rule_hdl;
+				IPACMDBG_H("IPv6 prefix MTU filter rule HDL:0x%x\n", ipv6_prefix_flt_rule_hdl[1]);
+			}
 			free(flt_rule);
 		}
 	}
@@ -4299,12 +4396,12 @@
 
 void IPACM_Lan::delete_ipv6_prefix_flt_rule()
 {
-	if(m_filtering.DeleteFilteringHdls(ipv6_prefix_flt_rule_hdl, IPA_IP_v6, NUM_IPV6_PREFIX_FLT_RULE) == false)
+	if(m_filtering.DeleteFilteringHdls(ipv6_prefix_flt_rule_hdl, IPA_IP_v6, NUM_IPV6_PREFIX_FLT_RULE + NUM_IPV6_PREFIX_MTU_RULE) == false)
 	{
-		IPACMERR("Failed to delete ipv6 prefix flt rule.\n");
+		IPACMERR("Failed to delete ipv6 prefix flt rules.\n");
 		return;
 	}
-	IPACM_Iface::ipacmcfg->decreaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v6, NUM_IPV6_PREFIX_FLT_RULE);
+	IPACM_Iface::ipacmcfg->decreaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v6, NUM_IPV6_PREFIX_FLT_RULE + NUM_IPV6_PREFIX_MTU_RULE);
 	return;
 }
 
@@ -6336,3 +6433,63 @@
 	}
 	return res;
 }
+
+int IPACM_Lan::construct_mtu_rule(struct ipa_flt_rule *rule, ipa_ip_type iptype, uint16_t mtu)
+{
+	int res = IPACM_SUCCESS;
+	int fd;
+	ipa_ioc_generate_flt_eq flt_eq;
+
+	if (rule == NULL)
+	{
+		IPACMERR("rule is empty");
+		return IPACM_FAILURE;
+	}
+
+	if (mtu == 0)
+	{
+		IPACMERR("mtu is uninitialized");
+		return IPACM_FAILURE;
+	}
+
+	IPACMDBG_H("Adding MTU rule for iptype = %d\n", iptype);
+
+	rule->eq_attrib_type = 1;
+	rule->eq_attrib.rule_eq_bitmap = 0;
+	rule->action = IPA_PASS_TO_EXCEPTION;
+
+	/* generate eq */
+	memset(&flt_eq, 0, sizeof(flt_eq));
+	memcpy(&flt_eq.attrib, &rule->attrib, sizeof(flt_eq.attrib));
+	flt_eq.ip = iptype;
+
+	fd = open(IPA_DEVICE_NAME, O_RDWR);
+	if (fd < 0)
+	{
+		IPACMERR("Failed opening %s.\n", IPA_DEVICE_NAME);
+		return IPACM_FAILURE;
+	}
+
+	if (0 != ioctl(fd, IPA_IOC_GENERATE_FLT_EQ, &flt_eq)) //define and cpy attribute to this struct
+	{
+		IPACMERR("Failed to get eq_attrib\n");
+		res = IPACM_FAILURE;
+		goto fail;
+	}
+	memcpy(&rule->eq_attrib,
+		&flt_eq.eq_attrib, sizeof(rule->eq_attrib));
+
+	//add IHL offsets
+	rule->eq_attrib.rule_eq_bitmap |= (1<<10);
+	rule->eq_attrib.num_ihl_offset_range_16 = 1;
+	if (iptype == IPA_IP_v4)
+		rule->eq_attrib.ihl_offset_range_16[0].offset = 0x82;
+	else
+		rule->eq_attrib.ihl_offset_range_16[0].offset = 0x84;
+	rule->eq_attrib.ihl_offset_range_16[0].range_low = mtu + 1;
+	rule->eq_attrib.ihl_offset_range_16[0].range_high = UINT16_MAX; //0xFFFF
+
+fail:
+	close(fd);
+	return res;
+}
diff --git a/ipacm/src/IPACM_Wan.cpp b/ipacm/src/IPACM_Wan.cpp
index db0304a..be3bffc 100644
--- a/ipacm/src/IPACM_Wan.cpp
+++ b/ipacm/src/IPACM_Wan.cpp
@@ -52,6 +52,7 @@
 #include "linux/ipa_qmi_service_v01.h"
 #ifdef FEATURE_IPACM_HAL
 #include "IPACM_OffloadManager.h"
+#include <IPACM_Netlink.h>
 #endif
 
 bool IPACM_Wan::wan_up = false;
@@ -91,6 +92,8 @@
 int	IPACM_Wan::ipa_if_num_tether_v6[IPA_MAX_IFACE_ENTRIES];
 #endif
 
+uint16_t IPACM_Wan::mtu_default_wan = DEFAULT_MTU_SIZE;
+
 IPACM_Wan::IPACM_Wan(int iface_index,
 	ipacm_wan_iface_type is_sta_mode,
 	uint8_t *mac_addr) : IPACM_Iface(iface_index)
@@ -129,6 +132,7 @@
 	ext_prop = NULL;
 	is_ipv6_frag_firewall_flt_rule_installed = false;
 	ipv6_frag_firewall_flt_rule_hdl = 0;
+	mtu_size = DEFAULT_MTU_SIZE;
 
 	num_wan_client = 0;
 	header_name_count = 0;
@@ -1818,6 +1822,9 @@
 	}
 	IPACMDBG_H("backhaul_is_wan_bridge ?: %d \n", IPACM_Wan::backhaul_is_wan_bridge);
 
+	/* query MTU size of the interface */
+	query_mtu_size();
+
 	if (m_is_sta_mode ==Q6_WAN)
 	{
 		IPACM_Wan::backhaul_mode = m_is_sta_mode;
@@ -1990,7 +1997,7 @@
 					IPACMDBG_H("hw-index-enable %d, counter %d\n", IPACM_Iface::ipacmcfg->hw_fnr_stats_support, IPACM_Iface::ipacmcfg->hw_counter_offset + UL_HW);
 					result = m_routing.AddRoutingRule_hw_index(rt_rule, IPACM_Iface::ipacmcfg->hw_counter_offset + UL_HW);
 				} else {
-					result = m_routing.AddRoutingRule(rt_rule);			
+					result = m_routing.AddRoutingRule(rt_rule);
 				}
 #else
 				result = m_routing.AddRoutingRule(rt_rule);
@@ -2105,6 +2112,11 @@
 				wan_route_rule_v6_hdl_a5[0], 0, iptype);
 	}
 
+	/* set mtu_default_wan to current default wan instance */
+	mtu_default_wan = mtu_size;
+
+	IPACMDBG_H("replace the mtu_default_wan to %d\n", mtu_default_wan);
+
 	ipacm_event_iface_up *wanup_data;
 	wanup_data = (ipacm_event_iface_up *)malloc(sizeof(ipacm_event_iface_up));
 	if (wanup_data == NULL)
@@ -2218,8 +2230,9 @@
 			IPACMDBG_H("dev %s add producer dependency\n", dev_name);
 			IPACMDBG_H("depend Got pipe %d rm index : %d \n", tx_prop->tx[0].dst_pipe, IPACM_Iface::ipacmcfg->ipa_client_rm_map_tbl[tx_prop->tx[0].dst_pipe]);
 			IPACM_Iface::ipacmcfg->AddRmDepend(IPACM_Iface::ipacmcfg->ipa_client_rm_map_tbl[tx_prop->tx[0].dst_pipe],false);
+	}
 #ifdef WAN_IOC_NOTIFY_WAN_STATE
-	} else {
+	else {
 			if ((m_is_sta_mode == Q6_WAN && ipa_pm_q6_check == 0 ) || (m_is_sta_mode == Q6_MHI_WAN))
 			{
 				fd_wwan_ioctl = open(WWAN_QMI_IOCTL_DEVICE_NAME, O_RDWR);
@@ -2240,9 +2253,8 @@
 			ipa_pm_q6_check++;
 			IPACMDBG_H("update ipa_pm_q6_check to %d\n", ipa_pm_q6_check);
 	}
-#else
-	}
 #endif
+
 	if(rt_rule != NULL)
 	{
 		free(rt_rule);
@@ -4989,8 +5001,9 @@
 			IPACMDBG_H("dev %s delete producer dependency\n", dev_name);
 			IPACMDBG_H("depend Got pipe %d rm index : %d \n", tx_prop->tx[0].dst_pipe, IPACM_Iface::ipacmcfg->ipa_client_rm_map_tbl[tx_prop->tx[0].dst_pipe]);
 			IPACM_Iface::ipacmcfg->DelRmDepend(IPACM_Iface::ipacmcfg->ipa_client_rm_map_tbl[tx_prop->tx[0].dst_pipe]);
+		}
 #ifdef WAN_IOC_NOTIFY_WAN_STATE
-		} else {
+		else {
 			IPACMDBG_H("ipa_pm_q6_check to %d\n", ipa_pm_q6_check);
 			if(ipa_pm_q6_check == 1)
 			{
@@ -5012,8 +5025,6 @@
 			else
 				IPACMERR(" ipa_pm_q6_check becomes negative !!!\n");
 		}
-#else
-}
 #endif
 		/* Delete the default route*/
 		if (iptype == IPA_IP_v6)
@@ -5554,6 +5565,9 @@
 		goto fail;
 	}
 
+	/* reset the mtu size */
+	mtu_size = DEFAULT_MTU_SIZE;
+
 	if(ip_type == IPA_IP_v4)
 	{
 		num_ipv4_modem_pdn--;
@@ -7913,3 +7927,33 @@
 	}
 	return res;
 }
+
+int IPACM_Wan::query_mtu_size()
+{
+	int fd;
+	struct ifreq if_mtu;
+
+	fd = socket(AF_INET, SOCK_DGRAM, 0);
+	if ( fd < 0 ) {
+		IPACMERR("ipacm: socket open failed [%d]\n", fd);
+		return IPACM_FAILURE;
+	}
+
+	strlcpy(if_mtu.ifr_name, dev_name, IFNAMSIZ);
+	IPACMDBG_H("device name: %s\n", dev_name);
+	if_mtu.ifr_name[IFNAMSIZ - 1] = '\0';
+
+	if ( ioctl(fd, SIOCGIFMTU, &if_mtu) < 0 ) {
+		IPACMERR("ioctl failed to get mtu\n");
+		close(fd);
+		return IPACM_FAILURE;
+	}
+	IPACMDBG_H("mtu=[%d]\n", if_mtu.ifr_mtu);
+	if (if_mtu.ifr_mtu < DEFAULT_MTU_SIZE) {
+		mtu_size = if_mtu.ifr_mtu;
+		IPACMDBG_H("replaced mtu=[%d] for (%s)\n", mtu_size, dev_name);
+	}
+
+	close(fd);
+	return IPACM_SUCCESS;
+}
diff --git a/ipacm/src/IPACM_Wlan.cpp b/ipacm/src/IPACM_Wlan.cpp
index 395f951..d5d38ca 100644
--- a/ipacm/src/IPACM_Wlan.cpp
+++ b/ipacm/src/IPACM_Wlan.cpp
@@ -1955,16 +1955,16 @@
 		}
 		/* delete private-ipv4 filter rules */
 #ifdef FEATURE_IPA_ANDROID
-		if(m_filtering.DeleteFilteringHdls(private_fl_rule_hdl, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES) == false)
+		if(m_filtering.DeleteFilteringHdls(private_fl_rule_hdl, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES) == false)
 		{
 			IPACMERR("Error deleting private subnet IPv4 flt rules.\n");
 			res = IPACM_FAILURE;
 			goto fail;
 		}
-		IPACM_Iface::ipacmcfg->decreaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES);
+		IPACM_Iface::ipacmcfg->decreaseFltRuleCount(rx_prop->rx[0].src_pipe, IPA_IP_v4, IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES);
 #else
-		num_private_subnet_fl_rule = IPACM_Iface::ipacmcfg->ipa_num_private_subnet > IPA_MAX_PRIVATE_SUBNET_ENTRIES?
-			IPA_MAX_PRIVATE_SUBNET_ENTRIES : IPACM_Iface::ipacmcfg->ipa_num_private_subnet;
+		num_private_subnet_fl_rule = IPACM_Iface::ipacmcfg->ipa_num_private_subnet > (IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES)?
+			(IPA_MAX_PRIVATE_SUBNET_ENTRIES + IPA_MAX_MTU_ENTRIES) : IPACM_Iface::ipacmcfg->ipa_num_private_subnet;
 		if(m_filtering.DeleteFilteringHdls(private_fl_rule_hdl, IPA_IP_v4, num_private_subnet_fl_rule) == false)
 		{
 			IPACMERR("Error deleting private subnet flt rules, aborting...\n");