From 7328021a7c3ede2399fb7bb7654be49f2bd7a75d Mon Sep 17 00:00:00 2001
From: Anton Evangelatov <anton.evangelatov@gmail.com>
Date: Fri, 9 Mar 2018 14:32:49 +0100
Subject: [PATCH] p2p/sim: fix comment and update ExternalIP

---
 p2p/simulations/adapters/docker.go |  2 +-
 p2p/simulations/adapters/exec.go   | 28 +++++++++-------------------
 2 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/p2p/simulations/adapters/docker.go b/p2p/simulations/adapters/docker.go
index 6cdeec7b5b..d145c46b3a 100644
--- a/p2p/simulations/adapters/docker.go
+++ b/p2p/simulations/adapters/docker.go
@@ -99,7 +99,7 @@ func (d *DockerAdapter) NewNode(config *NodeConfig) (Node, error) {
 	conf.Stack.P2P.NAT = nil
 	conf.Stack.NoUSB = true
 
-	// listen on a localhost port, which we set when we
+	// listen on all interfaces on a given port, which we set when we
 	// initialise NodeConfig (usually a random port)
 	conf.Stack.P2P.ListenAddr = fmt.Sprintf(":%d", config.Port)
 
diff --git a/p2p/simulations/adapters/exec.go b/p2p/simulations/adapters/exec.go
index 185123206c..a147e1e7b0 100644
--- a/p2p/simulations/adapters/exec.go
+++ b/p2p/simulations/adapters/exec.go
@@ -340,27 +340,17 @@ type execNodeConfig struct {
 
 // ExternalIP gets an external IP address so that Enode URL is usable
 func ExternalIP() net.IP {
-	//addrs, err := net.InterfaceAddrs()
-	//if err != nil {
-	//log.Crit("error getting IP address", "err", err)
-	//}
-	//for _, addr := range addrs {
-	//if ip, ok := addr.(*net.IPNet); ok && !ip.IP.IsLoopback() {
-	//return ip.IP
-	//}
-	//}
-	//log.Crit("unable to determine explicit IP address")
-	//return net.IP{127, 0, 0, 1}
-
-	conn, err := net.Dial("udp", "8.8.8.8:80")
+	addrs, err := net.InterfaceAddrs()
 	if err != nil {
-		panic(err)
+		log.Crit("error getting IP address", "err", err)
 	}
-	defer conn.Close()
-
-	localAddr := conn.LocalAddr().(*net.UDPAddr)
-
-	return localAddr.IP
+	for _, addr := range addrs {
+		if ip, ok := addr.(*net.IPNet); ok && !ip.IP.IsLoopback() && !ip.IP.IsLinkLocalUnicast() {
+			return ip.IP
+		}
+	}
+	log.Crit("unable to determine explicit IP address")
+	return net.IP{127, 0, 0, 1}
 }
 
 // execP2PNode starts a devp2p node when the current binary is executed with