diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index 4fa24cc1c..b0316c540 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -199,6 +199,7 @@ var (
 		utils.InsecureUnlockAllowedFlag,
 		utils.RPCGlobalGasCapFlag,
 		utils.RPCGlobalTxFeeCapFlag,
+		utils.AllowUnprotectedTxs,
 	}
 
 	whisperFlags = []cli.Flag{
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index ba643efcc..070b3a1de 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -593,6 +593,10 @@ var (
 		Name:  "preload",
 		Usage: "Comma separated list of JavaScript files to preload into the console",
 	}
+	AllowUnprotectedTxs = cli.BoolFlag{
+		Name:  "rpc.allow-unprotected-txs",
+		Usage: "Allow for unprotected (non EIP155 signed) transactions to be submitted via RPC",
+	}
 
 	// Network Settings
 	MaxPeersFlag = cli.IntFlag{
@@ -966,6 +970,9 @@ func setHTTP(ctx *cli.Context, cfg *node.Config) {
 	if ctx.GlobalIsSet(HTTPPathPrefixFlag.Name) {
 		cfg.HTTPPathPrefix = ctx.GlobalString(HTTPPathPrefixFlag.Name)
 	}
+	if ctx.GlobalIsSet(AllowUnprotectedTxs.Name) {
+		cfg.AllowUnprotectedTxs = ctx.GlobalBool(AllowUnprotectedTxs.Name)
+	}
 }
 
 // setGraphQL creates the GraphQL listener interface string from the set
diff --git a/eth/api_backend.go b/eth/api_backend.go
index 17de83a28..2569972e5 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -41,9 +41,10 @@ import (
 
 // EthAPIBackend implements ethapi.Backend for full nodes
 type EthAPIBackend struct {
-	extRPCEnabled bool
-	eth           *Ethereum
-	gpo           *gasprice.Oracle
+	extRPCEnabled       bool
+	allowUnprotectedTxs bool
+	eth                 *Ethereum
+	gpo                 *gasprice.Oracle
 }
 
 // ChainConfig returns the active chain configuration.
@@ -292,6 +293,10 @@ func (b *EthAPIBackend) ExtRPCEnabled() bool {
 	return b.extRPCEnabled
 }
 
+func (b *EthAPIBackend) UnprotectedAllowed() bool {
+	return b.allowUnprotectedTxs
+}
+
 func (b *EthAPIBackend) RPCGasCap() uint64 {
 	return b.eth.config.RPCGasCap
 }
diff --git a/eth/backend.go b/eth/backend.go
index 4170ecc94..044422763 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -222,7 +222,10 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 	eth.miner = miner.New(eth, &config.Miner, chainConfig, eth.EventMux(), eth.engine, eth.isLocalBlock)
 	eth.miner.SetExtra(makeExtraData(config.Miner.ExtraData))
 
-	eth.APIBackend = &EthAPIBackend{stack.Config().ExtRPCEnabled(), eth, nil}
+	eth.APIBackend = &EthAPIBackend{stack.Config().ExtRPCEnabled(), stack.Config().AllowUnprotectedTxs, eth, nil}
+	if eth.APIBackend.allowUnprotectedTxs {
+		log.Info("Unprotected transactions allowed")
+	}
 	gpoParams := config.GPO
 	if gpoParams.Default == nil {
 		gpoParams.Default = config.Miner.GasPrice
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index d3c007b9b..52b4f5f50 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -1555,6 +1555,10 @@ func SubmitTransaction(ctx context.Context, b Backend, tx *types.Transaction) (c
 	if err := checkTxFee(tx.GasPrice(), tx.Gas(), b.RPCTxFeeCap()); err != nil {
 		return common.Hash{}, err
 	}
+	if !b.UnprotectedAllowed() && !tx.Protected() {
+		// Ensure only eip155 signed transactions are submitted if EIP155Required is set.
+		return common.Hash{}, errors.New("only replay-protected (EIP-155) transactions allowed over RPC")
+	}
 	if err := b.SendTx(ctx, tx); err != nil {
 		return common.Hash{}, err
 	}
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index f0a4c0493..ebb088fef 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -45,8 +45,9 @@ type Backend interface {
 	ChainDb() ethdb.Database
 	AccountManager() *accounts.Manager
 	ExtRPCEnabled() bool
-	RPCGasCap() uint64    // global gas cap for eth_call over rpc: DoS protection
-	RPCTxFeeCap() float64 // global tx fee cap for all transaction related APIs
+	RPCGasCap() uint64        // global gas cap for eth_call over rpc: DoS protection
+	RPCTxFeeCap() float64     // global tx fee cap for all transaction related APIs
+	UnprotectedAllowed() bool // allows only for EIP155 transactions.
 
 	// Blockchain API
 	SetHead(number uint64)
diff --git a/les/api_backend.go b/les/api_backend.go
index 083961490..f5d2354b6 100644
--- a/les/api_backend.go
+++ b/les/api_backend.go
@@ -40,9 +40,10 @@ import (
 )
 
 type LesApiBackend struct {
-	extRPCEnabled bool
-	eth           *LightEthereum
-	gpo           *gasprice.Oracle
+	extRPCEnabled       bool
+	allowUnprotectedTxs bool
+	eth                 *LightEthereum
+	gpo                 *gasprice.Oracle
 }
 
 func (b *LesApiBackend) ChainConfig() *params.ChainConfig {
@@ -263,6 +264,10 @@ func (b *LesApiBackend) ExtRPCEnabled() bool {
 	return b.extRPCEnabled
 }
 
+func (b *LesApiBackend) UnprotectedAllowed() bool {
+	return b.allowUnprotectedTxs
+}
+
 func (b *LesApiBackend) RPCGasCap() uint64 {
 	return b.eth.config.RPCGasCap
 }
diff --git a/les/client.go b/les/client.go
index d08c9feba..faaf6095e 100644
--- a/les/client.go
+++ b/les/client.go
@@ -157,7 +157,7 @@ func New(stack *node.Node, config *ethconfig.Config) (*LightEthereum, error) {
 		rawdb.WriteChainConfig(chainDb, genesisHash, chainConfig)
 	}
 
-	leth.ApiBackend = &LesApiBackend{stack.Config().ExtRPCEnabled(), leth, nil}
+	leth.ApiBackend = &LesApiBackend{stack.Config().ExtRPCEnabled(), stack.Config().AllowUnprotectedTxs, leth, nil}
 	gpoParams := config.GPO
 	if gpoParams.Default == nil {
 		gpoParams.Default = config.Miner.GasPrice
diff --git a/node/config.go b/node/config.go
index 447a69505..ef1da15d7 100644
--- a/node/config.go
+++ b/node/config.go
@@ -191,6 +191,9 @@ type Config struct {
 	staticNodesWarning     bool
 	trustedNodesWarning    bool
 	oldGethResourceWarning bool
+
+	// AllowUnprotectedTxs allows non EIP-155 protected transactions to be send over RPC.
+	AllowUnprotectedTxs bool `toml:",omitempty"`
 }
 
 // IPCEndpoint resolves an IPC endpoint based on a configured value, taking into