diff --git a/msm8998/hal/src/HAL.cpp b/msm8998/hal/src/HAL.cpp
index 59f978d..e19a149 100644
--- a/msm8998/hal/src/HAL.cpp
+++ b/msm8998/hal/src/HAL.cpp
@@ -506,8 +506,7 @@
         BoolResult res = makeInputCheckFailure("Not initialized (setUpstreamParameters)");
         hidl_cb(res.success, res.errMsg);
         fl.setResult(res.success, res.errMsg);
-    }
-    else if (!v4AddrParser.addV4(v4Addr) && !v4Addr.empty()) {
+    } else if (!v4AddrParser.addV4(v4Addr) && !v4Addr.empty()) {
         BoolResult res = makeInputCheckFailure(v4AddrParser.getLastErrAsStr());
         hidl_cb(res.success, res.errMsg);
         fl.setResult(res.success, res.errMsg);
@@ -519,7 +518,7 @@
         BoolResult res = makeInputCheckFailure(v6GwParser.getLastErrAsStr());
         hidl_cb(res.success, res.errMsg);
         fl.setResult(res.success, res.errMsg);
-    } else {
+    } else if (iface.size()>= 1) {
         RET ipaReturn = mIPA->setUpstream(
                 iface.c_str(),
                 v4GwParser.getFirstPrefix(),
@@ -527,6 +526,15 @@
         BoolResult res = ipaResultToBoolResult(ipaReturn);
         hidl_cb(res.success, res.errMsg);
         fl.setResult(res.success, res.errMsg);
+    } else {
+	/* send NULL iface string when upstream down */
+        RET ipaReturn = mIPA->setUpstream(
+                NULL,
+                v4GwParser.getFirstPrefix(),
+                v6GwParser.getFirstPrefix());
+        BoolResult res = ipaResultToBoolResult(ipaReturn);
+        hidl_cb(res.success, res.errMsg);
+        fl.setResult(res.success, res.errMsg);
     }
 
     mLogs.addLog(fl);
diff --git a/msm8998/ipacm/inc/IPACM_OffloadManager.h b/msm8998/ipacm/inc/IPACM_OffloadManager.h
index 72070dd..bade0aa 100644
--- a/msm8998/ipacm/inc/IPACM_OffloadManager.h
+++ b/msm8998/ipacm/inc/IPACM_OffloadManager.h
@@ -96,7 +96,7 @@
 
 private:
 
-	std::list<const char *> valid_ifaces;
+	std::list<std::string> valid_ifaces;
 
 	bool upstream_v4_up;
 
diff --git a/msm8998/ipacm/src/IPACM_OffloadManager.cpp b/msm8998/ipacm/src/IPACM_OffloadManager.cpp
index ca54ea6..2061fd2 100644
--- a/msm8998/ipacm/src/IPACM_OffloadManager.cpp
+++ b/msm8998/ipacm/src/IPACM_OffloadManager.cpp
@@ -212,6 +212,13 @@
 		IPACMERR("fail to get iface index.\n");
 		return FAIL_INPUT_CHECK;
 	}
+	/* Iface is valid, add to list if not present */
+	if (std::find(valid_ifaces.begin(), valid_ifaces.end(), std::string(downstream_name)) == valid_ifaces.end())
+	{
+		/* Iface is new, add it to the list */
+		valid_ifaces.push_back(downstream_name);
+		IPACMDBG_H("add iface(%s) to list\n", downstream_name);
+	}
 
 	/* check if downstream netdev driver finished its configuration on IPA-HW */
 	if (IPACM_Iface::ipacmcfg->CheckNatIfaces(downstream_name))
@@ -263,13 +270,6 @@
 		return SUCCESS;
 	}
 
-	/* Iface is valid, add to list if not present */
-	if (std::find(valid_ifaces.begin(), valid_ifaces.end(), downstream_name) == valid_ifaces.end())
-	{
-		/* Iface is new, add it to the list */
-		valid_ifaces.push_back(downstream_name);
-	}
-
 	evt_data = (ipacm_event_ipahal_stream*)malloc(sizeof(ipacm_event_ipahal_stream));
 	if(evt_data == NULL)
 	{
@@ -303,7 +303,7 @@
 		IPACMERR("iface length is 0.\n");
 		return FAIL_HARDWARE;
 	}
-	if (std::find(valid_ifaces.begin(), valid_ifaces.end(), downstream_name) == valid_ifaces.end())
+	if (std::find(valid_ifaces.begin(), valid_ifaces.end(), std::string(downstream_name)) == valid_ifaces.end())
 	{
 		IPACMERR("iface is not present in list.\n");
 		return FAIL_HARDWARE;
@@ -493,12 +493,23 @@
 RET IPACM_OffloadManager::stopAllOffload()
 {
 	Prefix v4gw, v6gw;
+	RET result = SUCCESS;
+
 	memset(&v4gw, 0, sizeof(v4gw));
 	memset(&v6gw, 0, sizeof(v6gw));
 	v4gw.fam = V4;
 	v6gw.fam = V6;
 	IPACMDBG_H("posting setUpstream(NULL), ipv4-fam(%d) ipv6-fam(%d)\n", v4gw.fam, v6gw.fam);
-	return setUpstream(NULL, v4gw, v6gw);
+	result = setUpstream(NULL, v4gw, v6gw);
+
+	/* reset the event cache */
+	default_gw_index = INVALID_IFACE;
+	upstream_v4_up = false;
+	upstream_v6_up = false;
+	memset(event_cache, 0, MAX_EVENT_CACHE*sizeof(framework_event_cache));
+	latest_cache_index = 0;
+	valid_ifaces.clear();
+	return result;
 }
 
 RET IPACM_OffloadManager::setQuota(const char * upstream_name /* upstream */, uint64_t mb/* limit */)