From baa89cda93a97bfa7d3a7ab34e27222c77cd6e5d Mon Sep 17 00:00:00 2001
From: Kenneth VanderLinde <kwvanderlinde@gmail.com>
Date: Wed, 11 Sep 2024 23:14:30 -0700
Subject: [PATCH] Reject interfaces that have no addresses

Cherry-pick of 0ccc67329 from release-1.15 branch.
---
 src/main/java/net/rptools/maptool/util/UPnPUtil.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/main/java/net/rptools/maptool/util/UPnPUtil.java b/src/main/java/net/rptools/maptool/util/UPnPUtil.java
index 9303db187e..984c53cf5f 100644
--- a/src/main/java/net/rptools/maptool/util/UPnPUtil.java
+++ b/src/main/java/net/rptools/maptool/util/UPnPUtil.java
@@ -50,7 +50,9 @@ public static boolean findIGDs() {
         NetworkInterface ni = e.nextElement();
         try {
           var addresses = Collections.list(ni.getInetAddresses());
-          if (ni.isLoopback()) {
+          if (addresses.isEmpty()) {
+            log.info("UPnP:  Rejecting interface '{}' as it has no addresses", ni.getDisplayName());
+          } else if (ni.isLoopback()) {
             log.info(
                 "UPnP:  Rejecting interface '{}' [{}] as it is a loopback",
                 ni.getDisplayName(),