diff --git a/CHANGELOG.md b/CHANGELOG.md
index a378f4a0..24f8ae24 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -40,8 +40,9 @@ FEATURES:
 - [p2p] added new `/dial_peers&persistent=_` **unsafe** endpoint
 - [p2p] persistent node key in `$THMHOME/config/node_key.json`
 - [p2p] introduce peer ID and authenticate peers by ID using addresses like `ID@IP:PORT`
-- [p2p] new seed mode in pex reactor crawls the network and serves as a seed. TODO: `--p2p.seed_mode`
+- [p2p] new seed mode in pex reactor crawls the network and serves as a seed.
 - [config] MempoolConfig.CacheSize
+- [config] P2P.SeedMode (`--p2p.seed_mode`)
 
 IMPROVEMENT:
 - [p2p] stricter rules in the PEX reactor for better handling of abuse
diff --git a/cmd/tendermint/commands/run_node.go b/cmd/tendermint/commands/run_node.go
index 0eb7a425..76d61671 100644
--- a/cmd/tendermint/commands/run_node.go
+++ b/cmd/tendermint/commands/run_node.go
@@ -32,6 +32,7 @@ func AddNodeFlags(cmd *cobra.Command) {
 	cmd.Flags().String("p2p.persistent_peers", config.P2P.PersistentPeers, "Comma delimited host:port persistent peers")
 	cmd.Flags().Bool("p2p.skip_upnp", config.P2P.SkipUPNP, "Skip UPNP configuration")
 	cmd.Flags().Bool("p2p.pex", config.P2P.PexReactor, "Enable/disable Peer-Exchange")
+	cmd.Flags().Bool("p2p.seed_mode", config.P2P.SeedMode, "Enable/disable seed mode")
 
 	// consensus flags
 	cmd.Flags().Bool("consensus.create_empty_blocks", config.Consensus.CreateEmptyBlocks, "Set this to false to only produce blocks when there are txs or when the AppHash changes")
diff --git a/config/config.go b/config/config.go
index 6395c60f..abd57311 100644
--- a/config/config.go
+++ b/config/config.go
@@ -257,9 +257,6 @@ type P2PConfig struct {
 	// Set true for strict address routability rules
 	AddrBookStrict bool `mapstructure:"addr_book_strict"`
 
-	// Set true to enable the peer-exchange reactor
-	PexReactor bool `mapstructure:"pex"`
-
 	// Maximum number of peers to connect to
 	MaxNumPeers int `mapstructure:"max_num_peers"`
 
@@ -274,6 +271,15 @@ type P2PConfig struct {
 
 	// Rate at which packets can be received, in bytes/second
 	RecvRate int64 `mapstructure:"recv_rate"`
+
+	// Set true to enable the peer-exchange reactor
+	PexReactor bool `mapstructure:"pex"`
+
+	// Seed mode, in which node constantly crawls the network and looks for
+	// peers. If another node asks it for addresses, it responds and disconnects.
+	//
+	// Does not work if the peer-exchange reactor is disabled.
+	SeedMode bool `mapstructure:"seed_mode"`
 }
 
 // DefaultP2PConfig returns a default configuration for the peer-to-peer layer
@@ -288,6 +294,7 @@ func DefaultP2PConfig() *P2PConfig {
 		SendRate:                512000, // 500 kB/s
 		RecvRate:                512000, // 500 kB/s
 		PexReactor:              true,
+		SeedMode:                false,
 	}
 }
 
diff --git a/config/toml.go b/config/toml.go
index bdc9f5a6..e69cf37f 100644
--- a/config/toml.go
+++ b/config/toml.go
@@ -150,6 +150,15 @@ send_rate = {{ .P2P.SendRate }}
 # Rate at which packets can be received, in bytes/second
 recv_rate = {{ .P2P.RecvRate }}
 
+# Set true to enable the peer-exchange reactor
+pex = {{ .P2P.PexReactor }}
+
+# Seed mode, in which node constantly crawls the network and looks for
+# peers. If another node asks it for addresses, it responds and disconnects.
+#
+# Does not work if the peer-exchange reactor is disabled.
+seed_mode = {{ .P2P.SeedMode }}
+
 ##### mempool configuration options #####
 [mempool]
 
diff --git a/docs/specification/configuration.rst b/docs/specification/configuration.rst
index cf600290..d7c18600 100644
--- a/docs/specification/configuration.rst
+++ b/docs/specification/configuration.rst
@@ -112,6 +112,15 @@ like the file below, however, double check by inspecting the
     # Rate at which packets can be received, in bytes/second
     recv_rate = 512000
 
+    # Set true to enable the peer-exchange reactor
+    pex = true
+
+    # Seed mode, in which node constantly crawls the network and looks for
+    # peers. If another node asks it for addresses, it responds and disconnects.
+    #
+    # Does not work if the peer-exchange reactor is disabled.
+    seed_mode = false
+
     ##### mempool configuration options #####
     [mempool]
 
diff --git a/node/node.go b/node/node.go
index acf51a90..cd2b4bcb 100644
--- a/node/node.go
+++ b/node/node.go
@@ -259,7 +259,7 @@ func NewNode(config *cfg.Config,
 			seeds = strings.Split(config.P2P.Seeds, ",")
 		}
 		pexReactor := pex.NewPEXReactor(addrBook,
-			&pex.PEXReactorConfig{Seeds: seeds})
+			&pex.PEXReactorConfig{Seeds: seeds, SeedMode: config.P2P.SeedMode})
 		pexReactor.SetLogger(p2pLogger)
 		sw.AddReactor("PEX", pexReactor)
 	}