diff --git a/src/core/net/icmp6.cpp b/src/core/net/icmp6.cpp
index c8826f3c5..65a5ad90d 100644
--- a/src/core/net/icmp6.cpp
+++ b/src/core/net/icmp6.cpp
@@ -110,14 +110,16 @@ exit:
     return error;
 }
 
-ThreadError Icmp::SendError(const Address &aDestination, IcmpHeader::Type aType, IcmpHeader::Code aCode,
+ThreadError Icmp::SendError(IcmpHeader::Type aType, IcmpHeader::Code aCode, const MessageInfo &aMessageInfo,
                             const Header &aHeader)
 {
     ThreadError error = kThreadError_None;
-    MessageInfo messageInfo;
+    MessageInfo messageInfoLocal;
     Message *message = NULL;
     IcmpHeader icmp6Header;
 
+    messageInfoLocal = aMessageInfo;
+
     VerifyOrExit((message = mIp6.NewMessage(0)) != NULL, error = kThreadError_NoBufs);
     SuccessOrExit(error = message->SetLength(sizeof(icmp6Header) + sizeof(aHeader)));
 
@@ -128,9 +130,7 @@ ThreadError Icmp::SendError(const Address &aDestination, IcmpHeader::Type aType,
     icmp6Header.SetCode(aCode);
     message->Write(0, sizeof(icmp6Header), &icmp6Header);
 
-    messageInfo.SetPeerAddr(aDestination);
-
-    SuccessOrExit(error = mIp6.SendDatagram(*message, messageInfo, kProtoIcmp6));
+    SuccessOrExit(error = mIp6.SendDatagram(*message, messageInfoLocal, kProtoIcmp6));
 
     otLogInfoIcmp("Sent ICMPv6 Error");
 
diff --git a/src/core/net/icmp6.hpp b/src/core/net/icmp6.hpp
index b17c7d0a5..e7515f62d 100644
--- a/src/core/net/icmp6.hpp
+++ b/src/core/net/icmp6.hpp
@@ -95,7 +95,7 @@ public:
      */
     enum Type
     {
-        kTypeDstUnreach  = 0,     ///< Destination Unreachable
+        kTypeDstUnreach  = 1,     ///< Destination Unreachable
         kTypeEchoRequest = 128,   ///< Echo Request
         kTypeEchoReply   = 129,   ///< Echo Reply
     };
@@ -321,16 +321,16 @@ public:
     /**
      * This method sends an ICMPv6 error message.
      *
-     * @param[in]  aDestination  The IPv6 destination address.
      * @param[in]  aType         The ICMPv6 message type.
      * @param[in]  aCode         The ICMPv6 message code.
+     * @param[in]  aMessageInfo  A reference to the message info.
      * @param[in]  aHeader       The IPv6 header of the error-causing message.
      *
      * @retval kThreadError_None    Successfully enqueued the ICMPv6 error message.
      * @retval kThreadError_NoBufs  Insufficient buffers available.
      *
      */
-    ThreadError SendError(const Address &aDestination, IcmpHeader::Type aType, IcmpHeader::Code aCode,
+    ThreadError SendError(IcmpHeader::Type aType, IcmpHeader::Code aCode, const MessageInfo &aMessageInfo,
                           const Header &aHeader);
 
     /**
diff --git a/src/core/thread/mle.cpp b/src/core/thread/mle.cpp
index 85f3b72b8..461b83d9d 100644
--- a/src/core/thread/mle.cpp
+++ b/src/core/thread/mle.cpp
@@ -2994,7 +2994,7 @@ Router *Mle::GetParent()
 ThreadError Mle::CheckReachability(uint16_t aMeshSource, uint16_t aMeshDest, Ip6::Header &aIp6Header)
 {
     ThreadError error = kThreadError_Drop;
-    Ip6::Address dst;
+    Ip6::MessageInfo messageInfo;
 
     if (aMeshDest != GetRloc16())
     {
@@ -3006,10 +3006,13 @@ ThreadError Mle::CheckReachability(uint16_t aMeshSource, uint16_t aMeshDest, Ip6
         ExitNow(error = kThreadError_None);
     }
 
-    dst = GetMeshLocal16();
-    dst.mFields.m16[7] = HostSwap16(aMeshSource);
-    mNetif.GetIp6().mIcmp.SendError(dst, Ip6::IcmpHeader::kTypeDstUnreach, Ip6::IcmpHeader::kCodeDstUnreachNoRoute,
-                                    aIp6Header);
+    messageInfo.GetPeerAddr() = GetMeshLocal16();
+    messageInfo.GetPeerAddr().mFields.m16[7] = HostSwap16(aMeshSource);
+    messageInfo.SetInterfaceId(mNetif.GetInterfaceId());
+
+    mNetif.GetIp6().mIcmp.SendError(Ip6::IcmpHeader::kTypeDstUnreach,
+                                    Ip6::IcmpHeader::kCodeDstUnreachNoRoute,
+                                    messageInfo, aIp6Header);
 
 exit:
     return error;
diff --git a/src/core/thread/mle_router.cpp b/src/core/thread/mle_router.cpp
index 830c7102e..81ce3a96d 100644
--- a/src/core/thread/mle_router.cpp
+++ b/src/core/thread/mle_router.cpp
@@ -3542,7 +3542,7 @@ void MleRouter::ResolveRoutingLoops(uint16_t aSourceMac, uint16_t aDestRloc16)
 
 ThreadError MleRouter::CheckReachability(uint16_t aMeshSource, uint16_t aMeshDest, Ip6::Header &aIp6Header)
 {
-    Ip6::Address destination;
+    Ip6::MessageInfo messageInfo;
 
     if (mDeviceState == kDeviceStateChild)
     {
@@ -3577,10 +3577,13 @@ ThreadError MleRouter::CheckReachability(uint16_t aMeshSource, uint16_t aMeshDes
         return kThreadError_None;
     }
 
-    destination = GetMeshLocal16();
-    destination.mFields.m16[7] = HostSwap16(aMeshSource);
-    mNetif.GetIp6().mIcmp.SendError(destination, Ip6::IcmpHeader::kTypeDstUnreach,
-                                    Ip6::IcmpHeader::kCodeDstUnreachNoRoute, aIp6Header);
+    messageInfo.GetPeerAddr() = GetMeshLocal16();
+    messageInfo.GetPeerAddr().mFields.m16[7] = HostSwap16(aMeshSource);
+    messageInfo.SetInterfaceId(mNetif.GetInterfaceId());
+
+    mNetif.GetIp6().mIcmp.SendError(Ip6::IcmpHeader::kTypeDstUnreach,
+                                    Ip6::IcmpHeader::kCodeDstUnreachNoRoute,
+                                    messageInfo, aIp6Header);
 
     return kThreadError_Drop;
 }
diff --git a/tests/scripts/thread-cert/ipv6.py b/tests/scripts/thread-cert/ipv6.py
index 9a689c8d9..640823224 100644
--- a/tests/scripts/thread-cert/ipv6.py
+++ b/tests/scripts/thread-cert/ipv6.py
@@ -54,7 +54,7 @@ UPPER_LAYER_PROTOCOLS = [
 ]
 
 # ICMP Protocol codes
-ICMP_DESTINATION_UNREACHABLE = 0
+ICMP_DESTINATION_UNREACHABLE = 1
 ICMP_ECHO_REQUEST = 128
 ICMP_ECHO_RESPONSE = 129