diff --git a/src/protocol.cpp b/src/protocol.cpp
index 6a60d8c803..9d9063dc3c 100644
--- a/src/protocol.cpp
+++ b/src/protocol.cpp
@@ -135,6 +135,7 @@ bool operator<(const CInv &a, const CInv &b) {
 
 std::string CInv::GetCommand() const {
     std::string cmd;
+    if (type & MSG_EXT_FLAG) cmd.append("extblk-");
     switch (GetKind()) {
         case MSG_TX:
             return cmd.append(NetMsgType::TX);
diff --git a/src/test/inv_tests.cpp b/src/test/inv_tests.cpp
index 15e5911db8..6bad22f402 100644
--- a/src/test/inv_tests.cpp
+++ b/src/test/inv_tests.cpp
@@ -28,4 +28,19 @@ BOOST_AUTO_TEST_CASE(validate_kind) {
     CheckType(GetDataMsg::MSG_EXT_BLOCK, GetDataMsg::MSG_BLOCK, false, true);
 }
 
+static void CheckCommand(int type, std::string expected) {
+    CInv inv(type, uint256());
+    BOOST_CHECK_EQUAL(inv.GetCommand(), expected);
+}
+
+/* Validate various inv facilities. */
+BOOST_AUTO_TEST_CASE(validate_cmd) {
+    CheckCommand(GetDataMsg::MSG_TX, "tx");
+    CheckCommand(GetDataMsg::MSG_BLOCK, "block");
+    CheckCommand(GetDataMsg::MSG_FILTERED_BLOCK, "merkleblock");
+    CheckCommand(GetDataMsg::MSG_CMPCT_BLOCK, "cmpctblock");
+    CheckCommand(GetDataMsg::MSG_EXT_TX, "extblk-tx");
+    CheckCommand(GetDataMsg::MSG_EXT_BLOCK, "extblk-block");
+}
+
 BOOST_AUTO_TEST_SUITE_END()