diff --git a/transporthandler.cpp b/transporthandler.cpp
index 1a06ae5..c8dccb3 100644
--- a/transporthandler.cpp
+++ b/transporthandler.cpp
@@ -1334,6 +1334,10 @@
             {
                 return responseReqDataLenInvalid();
             }
+            if (rsvd)
+            {
+                return responseInvalidFieldRequest();
+            }
             auto status = static_cast<SetStatus>(static_cast<uint8_t>(flag));
             switch (status)
             {
@@ -1391,6 +1395,10 @@
             {
                 return responseReqDataLenInvalid();
             }
+            if (rsvd)
+            {
+                return responseInvalidFieldRequest();
+            }
             switch (static_cast<IPSrc>(static_cast<uint8_t>(flag)))
             {
                 case IPSrc::DHCP:
@@ -1516,6 +1524,10 @@
             {
                 return responseReqDataLenInvalid();
             }
+            if (rsvd)
+            {
+                return responseInvalidFieldRequest();
+            }
             copyInto(ip, ipbytes);
             if (enabled)
             {