diff --git a/README.md b/README.md
index edab6a7..5182930 100644
--- a/README.md
+++ b/README.md
@@ -43,6 +43,9 @@ In practice, you probably want to run this instead:
 
 This keeps a persistent set of keys (and by extension, IP address) and gives you the option of editing the configuration file.
 If you want to use it as an overlay network on top of e.g. the internet, then you can do so by adding the remote devices domain/address and port (as a string, e.g. `"1.2.3.4:5678"`) to the list of `Peers` in the configuration file.
+You can control whether or not it peers over TCP or UDP by adding `tcp:` or `udp:` to the start of the string, i.e. `"udp:1.2.3.4:5678"`.
+It is currently configured to accept incoming TCP and UDP connections.
+In the interest of testing the TCP machinery, it's set to create TCP connections for auto-peering (over link-local IPv6), and to use TCP by default if no transport is specified for a manually configured peer.
 
 ### Platforms
 
diff --git a/misc/yggdrasil.go.tcp b/misc/yggdrasil.go.tcp
deleted file mode 100644
index c2c9a6b..0000000
--- a/misc/yggdrasil.go.tcp
+++ /dev/null
@@ -1,283 +0,0 @@
-package main
-
-import "bytes"
-import "encoding/hex"
-import "encoding/json"
-import "flag"
-import "fmt"
-import "io/ioutil"
-import "net"
-import "os"
-import "os/signal"
-import "time"
-import "regexp"
-
-import _ "net/http/pprof"
-import "net/http"
-import "log"
-import "runtime"
-
-import "golang.org/x/net/ipv6"
-
-import . "yggdrasil"
-
-/**
-* This is a very crude wrapper around src/yggdrasil
-* It can generate a new config (--genconf)
-* It can read a config from stdin (--useconf)
-* It can run with an automatic config (--autoconf)
- */
-
-type nodeConfig struct {
-	Listen      string
-	AdminListen string
-	Peers       []string
-	BoxPub      string
-	BoxPriv     string
-	SigPub      string
-	SigPriv     string
-	Multicast   bool
-	LinkLocal   string
-	IfName      string
-}
-
-type node struct {
-	core Core
-	sock *ipv6.PacketConn
-}
-
-func (n *node) init(cfg *nodeConfig, logger *log.Logger) {
-	boxPub, err := hex.DecodeString(cfg.BoxPub)
-	if err != nil {
-		panic(err)
-	}
-	boxPriv, err := hex.DecodeString(cfg.BoxPriv)
-	if err != nil {
-		panic(err)
-	}
-	sigPub, err := hex.DecodeString(cfg.SigPub)
-	if err != nil {
-		panic(err)
-	}
-	sigPriv, err := hex.DecodeString(cfg.SigPriv)
-	if err != nil {
-		panic(err)
-	}
-	n.core.DEBUG_init(boxPub, boxPriv, sigPub, sigPriv)
-	n.core.DEBUG_setLogger(logger)
-	ifceExpr, err := regexp.Compile(cfg.LinkLocal)
-	if err != nil {
-		panic(err)
-	}
-	n.core.DEBUG_setIfceExpr(ifceExpr)
-	logger.Println("Starting interface...")
-	n.core.DEBUG_setupAndStartGlobalTCPInterface(cfg.Listen)
-	logger.Println("Started interface")
-	logger.Println("Starting admin socket...")
-	n.core.DEBUG_setupAndStartAdminInterface(cfg.AdminListen)
-	logger.Println("Started admin socket")
-	go func() {
-		if len(cfg.Peers) == 0 {
-			return
-		}
-		for {
-			for _, p := range cfg.Peers {
-				n.core.DEBUG_addTCPConn(p)
-				time.Sleep(time.Second)
-			}
-			time.Sleep(time.Minute)
-		}
-	}()
-}
-
-func generateConfig() *nodeConfig {
-	core := Core{}
-	bpub, bpriv := core.DEBUG_newBoxKeys()
-	spub, spriv := core.DEBUG_newSigKeys()
-	cfg := nodeConfig{}
-	cfg.Listen = "[::]:0"
-	cfg.AdminListen = "localhost:9001"
-	cfg.BoxPub = hex.EncodeToString(bpub[:])
-	cfg.BoxPriv = hex.EncodeToString(bpriv[:])
-	cfg.SigPub = hex.EncodeToString(spub[:])
-	cfg.SigPriv = hex.EncodeToString(spriv[:])
-	cfg.Peers = []string{}
-	cfg.Multicast = true
-	cfg.LinkLocal = ""
-	cfg.IfName = "auto"
-	return &cfg
-}
-
-func doGenconf() string {
-	cfg := generateConfig()
-	bs, err := json.MarshalIndent(cfg, "", "  ")
-	if err != nil {
-		panic(err)
-	}
-	return string(bs)
-}
-
-var multicastAddr = "[ff02::114]:9001"
-
-func (n *node) listen() {
-	groupAddr, err := net.ResolveUDPAddr("udp6", multicastAddr)
-	if err != nil {
-		panic(err)
-	}
-	bs := make([]byte, 2048)
-	for {
-		nBytes, rcm, fromAddr, err := n.sock.ReadFrom(bs)
-		if err != nil {
-			panic(err)
-		}
-		//if rcm == nil { continue } // wat
-		//fmt.Println("DEBUG:", "packet from:", fromAddr.String())
-		if rcm != nil {
-			// Windows can't set the flag needed to return a non-nil value here
-			// So only make these checks if we get something useful back
-			// TODO? Skip them always, I'm not sure if they're really needed...
-			if !rcm.Dst.IsLinkLocalMulticast() {
-				continue
-			}
-			if !rcm.Dst.Equal(groupAddr.IP) {
-				continue
-			}
-		}
-		anAddr := string(bs[:nBytes])
-		addr, err := net.ResolveTCPAddr("tcp6", anAddr)
-		if err != nil {
-			panic(err)
-			continue
-		} // Panic for testing, remove later
-		from := fromAddr.(*net.UDPAddr)
-		//fmt.Println("DEBUG:", "heard:", addr.IP.String(), "from:", from.IP.String())
-		if addr.IP.String() != from.IP.String() {
-			continue
-		}
-		addr.Zone = from.Zone
-		saddr := addr.String()
-		//if _, isIn := n.peers[saddr]; isIn { continue }
-		//n.peers[saddr] = struct{}{}
-		n.core.DEBUG_addTCPConn(saddr)
-		//fmt.Println("DEBUG:", "added multicast peer:", saddr)
-	}
-}
-
-func (n *node) announce() {
-	groupAddr, err := net.ResolveUDPAddr("udp6", multicastAddr)
-	if err != nil {
-		panic(err)
-	}
-	var anAddr net.TCPAddr
-	tcpAddr := n.core.DEBUG_getGlobalTCPAddr()
-	anAddr.Port = tcpAddr.Port
-	destAddr, err := net.ResolveUDPAddr("udp6", multicastAddr)
-	if err != nil {
-		panic(err)
-	}
-	for {
-		ifaces, err := net.Interfaces()
-		if err != nil {
-			panic(err)
-		}
-		for _, iface := range ifaces {
-			n.sock.JoinGroup(&iface, groupAddr)
-			//err := n.sock.JoinGroup(&iface, groupAddr)
-			//if err != nil { panic(err) }
-			addrs, err := iface.Addrs()
-			if err != nil {
-				panic(err)
-			}
-			for _, addr := range addrs {
-				addrIP, _, _ := net.ParseCIDR(addr.String())
-				if addrIP.To4() != nil {
-					continue
-				} // IPv6 only
-				if !addrIP.IsLinkLocalUnicast() {
-					continue
-				}
-				anAddr.IP = addrIP
-				anAddr.Zone = iface.Name
-				destAddr.Zone = iface.Name
-				msg := []byte(anAddr.String())
-				n.sock.WriteTo(msg, nil, destAddr)
-				break
-			}
-			time.Sleep(time.Second)
-		}
-		time.Sleep(time.Second)
-	}
-}
-
-var pprof = flag.Bool("pprof", false, "Run pprof, see http://localhost:6060/debug/pprof/")
-var genconf = flag.Bool("genconf", false, "print a new config to stdout")
-var useconf = flag.Bool("useconf", false, "read config from stdin")
-var autoconf = flag.Bool("autoconf", false, "automatic mode (dynamic IP, peer with IPv6 neighbors)")
-
-func main() {
-	flag.Parse()
-	var cfg *nodeConfig
-	switch {
-	case *autoconf:
-		cfg = generateConfig()
-	case *useconf:
-		config, err := ioutil.ReadAll(os.Stdin)
-		if err != nil {
-			panic(err)
-		}
-		decoder := json.NewDecoder(bytes.NewReader(config))
-		cfg = generateConfig()
-		err = decoder.Decode(cfg)
-		if err != nil {
-			panic(err)
-		}
-	case *genconf:
-		fmt.Println(doGenconf())
-	default:
-		flag.PrintDefaults()
-	}
-	if cfg == nil {
-		return
-	}
-	logger := log.New(os.Stdout, "", log.Flags())
-	if *pprof {
-		runtime.SetBlockProfileRate(1)
-		go func() { log.Println(http.ListenAndServe("localhost:6060", nil)) }()
-	}
-	// Setup
-	logger.Println("Initializing...")
-	n := node{}
-	n.init(cfg, logger)
-	logger.Println("Starting tun...")
-	//n.core.DEBUG_startTun(cfg.IfName) // 1280, the smallest supported MTU
-	n.core.DEBUG_startTunWithMTU(cfg.IfName, 65535) // Largest supported MTU
-	defer func() {
-		logger.Println("Closing...")
-		n.core.DEBUG_stopTun()
-	}()
-	logger.Println("Started...")
-	if cfg.Multicast {
-		addr, err := net.ResolveUDPAddr("udp", multicastAddr)
-		if err != nil {
-			panic(err)
-		}
-		listenString := fmt.Sprintf("[::]:%v", addr.Port)
-		conn, err := net.ListenPacket("udp6", listenString)
-		if err != nil {
-			panic(err)
-		}
-		//defer conn.Close() // Let it close on its own when the application exits
-		n.sock = ipv6.NewPacketConn(conn)
-		if err = n.sock.SetControlMessage(ipv6.FlagDst, true); err != nil {
-			// Windows can't set this flag, so we need to handle it in other ways
-			//panic(err)
-		}
-		go n.listen()
-		go n.announce()
-	}
-	// Catch interrupt to exit gracefully
-	c := make(chan os.Signal, 1)
-	signal.Notify(c, os.Interrupt, os.Kill)
-	<-c
-	logger.Println("Stopping...")
-}
diff --git a/src/yggdrasil/udp.go b/src/yggdrasil/udp.go
index 4e28f36..990a089 100644
--- a/src/yggdrasil/udp.go
+++ b/src/yggdrasil/udp.go
@@ -319,7 +319,7 @@ func (iface *udpInterface) reader() {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-const udp_chunkSize = 1024
+const udp_chunkSize = 508 // Apparently the maximum guaranteed safe IPv4 size
 
 func udp_decode(bs []byte) (chunks, chunk, count uint8, payload []byte) {
 	if len(bs) >= 3 {
diff --git a/yggdrasil.go b/yggdrasil.go
index e583b18..efb6151 100644
--- a/yggdrasil.go
+++ b/yggdrasil.go
@@ -71,7 +71,8 @@ func (n *node) init(cfg *nodeConfig, logger *log.Logger) {
 	}
 	n.core.DEBUG_setIfceExpr(ifceExpr)
 	logger.Println("Starting interface...")
-	n.core.DEBUG_setupAndStartGlobalUDPInterface(cfg.Listen)
+	n.core.DEBUG_setupAndStartGlobalTCPInterface(cfg.Listen) // Listen for peers on TCP
+  n.core.DEBUG_setupAndStartGlobalUDPInterface(cfg.Listen) // Also listen on UDP, TODO allow separate configuration for ip/port to listen on each of these
 	logger.Println("Started interface")
 	logger.Println("Starting admin socket...")
 	n.core.DEBUG_setupAndStartAdminInterface(cfg.AdminListen)
@@ -82,7 +83,11 @@ func (n *node) init(cfg *nodeConfig, logger *log.Logger) {
 		}
 		for {
 			for _, p := range cfg.Peers {
-				n.core.DEBUG_maybeSendUDPKeys(p)
+        switch {
+          case len(p) >= 4 && p[:4] == "udp:": n.core.DEBUG_maybeSendUDPKeys(p[4:])
+          case len(p) >= 4 && p[:4] == "tcp:": n.core.DEBUG_addTCPConn(p[4:])
+          default: n.core.DEBUG_addTCPConn(p)
+        }
 				time.Sleep(time.Second)
 			}
 			time.Sleep(time.Minute)
@@ -144,7 +149,7 @@ func (n *node) listen() {
 			}
 		}
 		anAddr := string(bs[:nBytes])
-		addr, err := net.ResolveUDPAddr("udp6", anAddr)
+		addr, err := net.ResolveTCPAddr("tcp6", anAddr)
 		if err != nil {
 			panic(err)
 			continue
@@ -158,7 +163,7 @@ func (n *node) listen() {
 		saddr := addr.String()
 		//if _, isIn := n.peers[saddr]; isIn { continue }
 		//n.peers[saddr] = struct{}{}
-		n.core.DEBUG_maybeSendUDPKeys(saddr)
+		n.core.DEBUG_addTCPConn(saddr) // FIXME? can result in 2 connections per peer
 		//fmt.Println("DEBUG:", "added multicast peer:", saddr)
 	}
 }
@@ -168,9 +173,9 @@ func (n *node) announce() {
 	if err != nil {
 		panic(err)
 	}
-	var anAddr net.UDPAddr
-	udpAddr := n.core.DEBUG_getGlobalUDPAddr()
-	anAddr.Port = udpAddr.Port
+	var anAddr net.TCPAddr
+	tcpAddr := n.core.DEBUG_getGlobalTCPAddr()
+	anAddr.Port = tcpAddr.Port
 	destAddr, err := net.ResolveUDPAddr("udp6", multicastAddr)
 	if err != nil {
 		panic(err)