--- loncom/auth/lonshibauth.pm	2021/09/21 22:54:26	1.6
+++ loncom/auth/lonshibauth.pm	2021/10/07 15:51:16	1.7
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Redirect Shibboleth authentication to designated URL (/adm/sso).
 #
-# $Id: lonshibauth.pm,v 1.6 2021/09/21 22:54:26 raeburn Exp $
+# $Id: lonshibauth.pm,v 1.7 2021/10/07 15:51:16 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -85,7 +85,10 @@ sub handler {
         my $protocol = $Apache::lonnet::protocol{$lonhost};
         unless ($protocol eq 'https') { $protocol = 'http'; }
         my $alias = &Apache::lonnet::use_proxy_alias($r,$lonhost);
-        $hostname = $alias if ($alias ne '');
+        if (($alias ne '') &&
+            (&Apache::lonnet::alias_shibboleth($lonhost))) {
+            $hostname = $alias;
+        }
         my $dest = $protocol.'://'.$hostname.$target;
         $r->subprocess_env;
         if ($ENV{'QUERY_STRING'} ne '') {