diff --git a/core/java/src/net/i2p/crypto/SelfSignedGenerator.java b/core/java/src/net/i2p/crypto/SelfSignedGenerator.java
index 773b7a7b89..bac548f184 100644
--- a/core/java/src/net/i2p/crypto/SelfSignedGenerator.java
+++ b/core/java/src/net/i2p/crypto/SelfSignedGenerator.java
@@ -676,6 +676,9 @@ private static byte[] getExtensions(byte[] pubbytes, String cname, Set<String> a
             altNames.add("localhost");
             altNames.add("127.0.0.1");
             altNames.add("::1");
+            // RFC 9476
+            if (cname.endsWith(".i2p"))
+                altNames.add(cname + ".alt");
         }
         for (String n : altNames) {
             int len;