diff --git a/router/java/src/net/i2p/router/transport/TransportUtil.java b/router/java/src/net/i2p/router/transport/TransportUtil.java
index 67402c8ee6ca2f183a84d63f08d998097f8de95f..e00f094f0a2baf37e874491559952dda2b93e1da 100644
--- a/router/java/src/net/i2p/router/transport/TransportUtil.java
+++ b/router/java/src/net/i2p/router/transport/TransportUtil.java
@@ -131,7 +131,7 @@ public abstract class TransportUtil {
         if (host != null)
             return host.contains(":");
         String caps = addr.getOption("caps");
-        return caps != null && caps.contains("6");
+        return caps != null && caps.contains(TransportImpl.CAP_IPV6) && !caps.contains(TransportImpl.CAP_IPV4);
     }
 
     /**