--- loncom/auth/lonshibauth.pm	2015/05/17 17:34:43	1.3
+++ loncom/auth/lonshibauth.pm	2021/05/04 18:47:37	1.4
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Redirect Shibboleth authentication to designated URL (/adm/sso).
 #
-# $Id: lonshibauth.pm,v 1.3 2015/05/17 17:34:43 raeburn Exp $
+# $Id: lonshibauth.pm,v 1.4 2021/05/04 18:47:37 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -80,6 +80,8 @@ sub handler {
         if (!$hostname) { $hostname = $r->hostname(); }
         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 '');
         my $dest = $protocol.'://'.$hostname.$target;
         $r->subprocess_env;
         if ($ENV{'QUERY_STRING'} ne '') {