--- loncom/auth/switchserver.pm	2010/03/22 20:11:08	1.25
+++ loncom/auth/switchserver.pm	2010/07/20 02:42:33	1.27
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Switch Servers Handler
 #
-# $Id: switchserver.pm,v 1.25 2010/03/22 20:11:08 droeschl Exp $
+# $Id: switchserver.pm,v 1.27 2010/07/20 02:42:33 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -83,7 +83,7 @@ sub handler {
 	    $env{'form.otherserver'} = 
 		&Apache::lonnet::spareserver(30000,undef,1);
 	}
-
+        
 	$switch_to=&Apache::lonnet::hostname($env{'form.otherserver'});
     }
 
@@ -95,6 +95,26 @@ sub handler {
 	return &do_redirect($r,$url,1)
     }
 
+    my $canhost = 1;
+    my $uprimary_id = &Apache::lonnet::domain($env{'user.domain'},'primary');
+    my $uint_dom = &Apache::lonnet::internet_dom($uprimary_id);
+    my @intdoms = &Apache::lonnet::get_internet_names($env{'form.otherserver'});
+    unless ($uint_dom ne '' && grep(/^\Q$uint_dom\E$/,@intdoms)) {
+        my $serverhomeID = &Apache::lonnet::get_server_homeID($switch_to);
+        my $serverhomedom = &Apache::lonnet::host_domain($serverhomeID);
+        my %defdomdefaults = &Apache::lonnet::get_domain_defaults($serverhomedom);
+        my %udomdefaults = &Apache::lonnet::get_domain_defaults($env{'user.domain'});
+        my $remoterev = &Apache::lonnet::get_server_loncaparev($env{'user.domain'},$env{'form.otherserver'});
+        $canhost = 
+            &Apache::lonnet::can_host_session($env{'user.domain'},
+                                              $env{'form.otherserver'},
+                                              $remoterev,
+                                              $udomdefaults{'remotesessions'},
+                                              $defdomdefaults{'hostedsessions'});
+    }
+
+    unless ($canhost) { return FORBIDDEN; }
+
     if ($env{'form.role'} && 
 	!exists($env{'user.role.'.$env{'form.role'}})) { return FORBIDDEN; }