diff --git a/lib/krb5/principal.c b/lib/krb5/principal.c
index 0227da5b1..47dcccc2a 100644
--- a/lib/krb5/principal.c
+++ b/lib/krb5/principal.c
@@ -540,11 +540,20 @@ struct v4_name_convert {
     { NULL, NULL }
 };
 
+/*
+ * return the converted instance name of `name' in `realm'.
+ * look in the configuration file and then in the default set above.
+ * return NULL if no conversion is appropriate.
+ */
+
 static const char*
-get_name_conversion(krb5_context context, const char *realm, const char *name)
+get_name_conversion(krb5_context context,
+		    const char *realm,
+		    const char *name)
 {
     struct v4_name_convert *q;
     const char *p;
+
     p = krb5_config_get_string(context, NULL, "realms", realm,
 			       "v4_name_convert", "host", name, NULL);
     if(p == NULL)
@@ -577,6 +586,12 @@ get_name_conversion(krb5_context context, const char *realm, const char *name)
     return NULL;
 }
 
+/*
+ * convert the v4 principal `name.instance@realm' to a v5 principal in `princ'.
+ * if `resolve', use DNS.
+ * if `func', use that function for validating the conversion
+ */
+
 krb5_error_code
 krb5_425_conv_principal_ext(krb5_context context,
 			    const char *name,
@@ -590,6 +605,7 @@ krb5_425_conv_principal_ext(krb5_context context,
     krb5_error_code ret;
     krb5_principal pr;
     char host[128];
+    char *low_realm = NULL;
 
     /* do the following: if the name is found in the
        `v4_name_convert:host' part, is is assumed to be a `host' type
@@ -673,15 +689,19 @@ krb5_425_conv_principal_ext(krb5_context context,
     p = krb5_config_get_string(context, NULL, "realms", realm, 
 			       "default_domain", NULL);
     if(p == NULL){
-	/* should this be an error or should it silently
-	   succeed? */
-	return HEIM_ERR_V4_PRINC_NO_CONV;
+	low_realm = strdup (realm);
+	if (low_realm == NULL)
+	    return ENOMEM;
+	strlwr (low_realm);
+	p = low_realm;
     }
 	
     if (*p == '.')
 	++p;
     snprintf(host, sizeof(host), "%s.%s", instance, p);
     ret = krb5_make_principal(context, &pr, realm, name, host, NULL);
+    if (low_realm)
+	free (low_realm);
     if(func == NULL || (*func)(context, pr)){
 	*princ = pr;
 	return 0;