diff --git a/eth/config.go b/eth/config.go
index aff2b170cc..2eaf21fbc3 100644
--- a/eth/config.go
+++ b/eth/config.go
@@ -95,9 +95,9 @@ type Config struct {
 	NetworkId uint64 // Network ID to use for selecting peers to connect to
 	SyncMode  downloader.SyncMode
 
-	// Discovery options
-	DisableDNSDiscovery bool
-	DiscoveryURLs       []string
+	// This can be set to list of enrtree:// URLs which will be queried for
+	// for nodes to connect to.
+	DiscoveryURLs []string
 
 	NoPruning  bool // Whether to disable pruning and flush everything to disk
 	NoPrefetch bool // Whether to disable prefetching and only load state on demand
@@ -160,8 +160,8 @@ type Config struct {
 	CheckpointOracle *params.CheckpointOracleConfig `toml:",omitempty"`
 
 	// Istanbul block override (TODO: remove after the fork)
-	OverrideIstanbul *big.Int
+	OverrideIstanbul *big.Int `toml:",omitempty"`
 
 	// MuirGlacier block override (TODO: remove after the fork)
-	OverrideMuirGlacier *big.Int
+	OverrideMuirGlacier *big.Int `toml:",omitempty"`
 }
diff --git a/eth/discovery.go b/eth/discovery.go
index e0e539b7d8..97d6322ca1 100644
--- a/eth/discovery.go
+++ b/eth/discovery.go
@@ -17,23 +17,14 @@
 package eth
 
 import (
-	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/forkid"
 	"github.com/ethereum/go-ethereum/p2p"
 	"github.com/ethereum/go-ethereum/p2p/dnsdisc"
 	"github.com/ethereum/go-ethereum/p2p/enode"
-	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
-var knownDNSNetworks = map[common.Hash]string{
-	params.MainnetGenesisHash: "enrtree://AMBMWDM3J6UY3M32TMMROUNLX6Y3YTLVC3DC6HN2AVG5NHNSAXDW6@all.mainnet.nodes.ethflare.xyz",
-	params.TestnetGenesisHash: "enrtree://AMBMWDM3J6UY3M32TMMROUNLX6Y3YTLVC3DC6HN2AVG5NHNSAXDW6@all.ropsten.nodes.ethflare.xyz",
-	params.RinkebyGenesisHash: "enrtree://AMBMWDM3J6UY3M32TMMROUNLX6Y3YTLVC3DC6HN2AVG5NHNSAXDW6@all.rinkeby.nodes.ethflare.xyz",
-	params.GoerliGenesisHash:  "enrtree://AMBMWDM3J6UY3M32TMMROUNLX6Y3YTLVC3DC6HN2AVG5NHNSAXDW6@all.goerli.nodes.ethflare.xyz",
-}
-
 // ethEntry is the "eth" ENR entry which advertises eth protocol
 // on the discovery network.
 type ethEntry struct {
@@ -74,17 +65,9 @@ func (eth *Ethereum) currentEthEntry() *ethEntry {
 
 // setupDiscovery creates the node discovery source for the eth protocol.
 func (eth *Ethereum) setupDiscovery(cfg *p2p.Config) (enode.Iterator, error) {
-	if cfg.NoDiscovery || eth.config.DisableDNSDiscovery {
+	if cfg.NoDiscovery || len(eth.config.DiscoveryURLs) == 0 {
 		return nil, nil
 	}
-	known := knownDNSNetworks[eth.blockchain.Genesis().Hash()]
-	urls := eth.config.DiscoveryURLs
-	if len(urls) == 0 {
-		if known == "" {
-			return nil, nil
-		}
-		urls = []string{known}
-	}
 	client := dnsdisc.NewClient(dnsdisc.Config{})
-	return client.NewIterator(urls...)
+	return client.NewIterator(eth.config.DiscoveryURLs...)
 }
diff --git a/eth/gen_config.go b/eth/gen_config.go
index bc4b55b120..1c659c393c 100644
--- a/eth/gen_config.go
+++ b/eth/gen_config.go
@@ -21,6 +21,7 @@ func (c Config) MarshalTOML() (interface{}, error) {
 		Genesis                 *core.Genesis `toml:",omitempty"`
 		NetworkId               uint64
 		SyncMode                downloader.SyncMode
+		DiscoveryURLs           []string
 		NoPruning               bool
 		NoPrefetch              bool
 		Whitelist               map[uint64]common.Hash `toml:"-"`
@@ -49,11 +50,14 @@ func (c Config) MarshalTOML() (interface{}, error) {
 		RPCGasCap               *big.Int                       `toml:",omitempty"`
 		Checkpoint              *params.TrustedCheckpoint      `toml:",omitempty"`
 		CheckpointOracle        *params.CheckpointOracleConfig `toml:",omitempty"`
+		OverrideIstanbul        *big.Int                       `toml:",omitempty"`
+		OverrideMuirGlacier     *big.Int                       `toml:",omitempty"`
 	}
 	var enc Config
 	enc.Genesis = c.Genesis
 	enc.NetworkId = c.NetworkId
 	enc.SyncMode = c.SyncMode
+	enc.DiscoveryURLs = c.DiscoveryURLs
 	enc.NoPruning = c.NoPruning
 	enc.NoPrefetch = c.NoPrefetch
 	enc.Whitelist = c.Whitelist
@@ -82,6 +86,8 @@ func (c Config) MarshalTOML() (interface{}, error) {
 	enc.RPCGasCap = c.RPCGasCap
 	enc.Checkpoint = c.Checkpoint
 	enc.CheckpointOracle = c.CheckpointOracle
+	enc.OverrideIstanbul = c.OverrideIstanbul
+	enc.OverrideMuirGlacier = c.OverrideMuirGlacier
 	return &enc, nil
 }
 
@@ -91,6 +97,7 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 		Genesis                 *core.Genesis `toml:",omitempty"`
 		NetworkId               *uint64
 		SyncMode                *downloader.SyncMode
+		DiscoveryURLs           []string
 		NoPruning               *bool
 		NoPrefetch              *bool
 		Whitelist               map[uint64]common.Hash `toml:"-"`
@@ -119,6 +126,8 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 		RPCGasCap               *big.Int                       `toml:",omitempty"`
 		Checkpoint              *params.TrustedCheckpoint      `toml:",omitempty"`
 		CheckpointOracle        *params.CheckpointOracleConfig `toml:",omitempty"`
+		OverrideIstanbul        *big.Int                       `toml:",omitempty"`
+		OverrideMuirGlacier     *big.Int                       `toml:",omitempty"`
 	}
 	var dec Config
 	if err := unmarshal(&dec); err != nil {
@@ -133,6 +142,9 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 	if dec.SyncMode != nil {
 		c.SyncMode = *dec.SyncMode
 	}
+	if dec.DiscoveryURLs != nil {
+		c.DiscoveryURLs = dec.DiscoveryURLs
+	}
 	if dec.NoPruning != nil {
 		c.NoPruning = *dec.NoPruning
 	}
@@ -217,5 +229,11 @@ func (c *Config) UnmarshalTOML(unmarshal func(interface{}) error) error {
 	if dec.CheckpointOracle != nil {
 		c.CheckpointOracle = dec.CheckpointOracle
 	}
+	if dec.OverrideIstanbul != nil {
+		c.OverrideIstanbul = dec.OverrideIstanbul
+	}
+	if dec.OverrideMuirGlacier != nil {
+		c.OverrideMuirGlacier = dec.OverrideMuirGlacier
+	}
 	return nil
 }