From 92c94011f107a2498596105b3f489e2eba2be36c Mon Sep 17 00:00:00 2001
From: Klaus Post <klauspost@gmail.com>
Date: Mon, 9 Aug 2021 15:57:54 +0200
Subject: [PATCH] Skip downed interfaces on Windows (#12910)

Disregard interfaces that are down when selecting bind addresses

Windows often has a number of disabled NICs used for VPN and other services.

This often causes minio to select an address for contacting the console that is on a disabled (virtual) NIC.

This checks if the interface is up before adding it to the pool on Windows.
---
 cmd/net.go | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/cmd/net.go b/cmd/net.go
index 32e367232..1371e442f 100644
--- a/cmd/net.go
+++ b/cmd/net.go
@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"net"
 	"net/url"
+	"runtime"
 	"sort"
 	"strings"
 
@@ -46,20 +47,30 @@ func mustSplitHostPort(hostPort string) (host, port string) {
 // mustGetLocalIP4 returns IPv4 addresses of localhost.  It panics on error.
 func mustGetLocalIP4() (ipList set.StringSet) {
 	ipList = set.NewStringSet()
-	addrs, err := net.InterfaceAddrs()
+	ifs, err := net.Interfaces()
 	logger.FatalIf(err, "Unable to get IP addresses of this host")
 
-	for _, addr := range addrs {
-		var ip net.IP
-		switch v := addr.(type) {
-		case *net.IPNet:
-			ip = v.IP
-		case *net.IPAddr:
-			ip = v.IP
+	for _, interf := range ifs {
+		addrs, err := interf.Addrs()
+		if err != nil {
+			continue
+		}
+		if runtime.GOOS == "windows" && interf.Flags&net.FlagUp == 0 {
+			continue
 		}
 
-		if ip.To4() != nil {
-			ipList.Add(ip.String())
+		for _, addr := range addrs {
+			var ip net.IP
+			switch v := addr.(type) {
+			case *net.IPNet:
+				ip = v.IP
+			case *net.IPAddr:
+				ip = v.IP
+			}
+
+			if ip.To4() != nil {
+				ipList.Add(ip.String())
+			}
 		}
 	}