diff --git a/src/main.cpp b/src/main.cpp
index a9311e2ceb9..e80ecaa0d48 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1138,7 +1138,14 @@ bool CTransaction::ConnectInputs(MapPrevTx inputs,
             {
                 // Verify signature
                 if (!VerifySignature(txPrev, *this, i, fStrictPayToScriptHash, 0))
+                {
+                    // only during transition phase for P2SH: do not invoke anti-DoS code for
+                    // potentially old clients relaying bad P2SH transactions
+                    if (fStrictPayToScriptHash && VerifySignature(txPrev, *this, i, false, 0))
+                        return error("ConnectInputs() : %s P2SH VerifySignature failed", GetHash().ToString().substr(0,10).c_str());
+
                     return DoS(100,error("ConnectInputs() : %s VerifySignature failed", GetHash().ToString().substr(0,10).c_str()));
+                }
             }
 
             // Mark outpoints as spent