diff --git a/src/internet/model/tcp-option.cc b/src/internet/model/tcp-option.cc
index ccbdebd35..341ac8fbb 100644
--- a/src/internet/model/tcp-option.cc
+++ b/src/internet/model/tcp-option.cc
@@ -95,8 +95,6 @@ TcpOption::IsKindKnown (uint8_t kind)
     case NOP:
     case MSS:
     case WINSCALE:
-    case SACK_PERM:
-    case SACK:
     case TS:
       return true;
     }
diff --git a/src/internet/model/tcp-option.h b/src/internet/model/tcp-option.h
index 7b474b0fb..90eff1ff3 100644
--- a/src/internet/model/tcp-option.h
+++ b/src/internet/model/tcp-option.h
@@ -50,12 +50,12 @@ public:
    */
   enum Kind
   {
+    // Remember to extend IsKindKnown() with new value, when adding values here
+    //
     END = 0,      //!< END
     NOP = 1,      //!< NOP
     MSS = 2,      //!< MSS
     WINSCALE = 3, //!< WINSCALE
-    SACK_PERM = 4,//!< SACK_PERM
-    SACK = 5,     //!< SACK
     TS = 8        //!< TS
   };