--- loncom/lonnet/perl/lonnet.pm	2017/06/22 02:11:28	1.1172.2.93.4.2
+++ loncom/lonnet/perl/lonnet.pm	2017/10/14 21:27:51	1.1172.2.93.4.3
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.1172.2.93.4.2 2017/06/22 02:11:28 raeburn Exp $
+# $Id: lonnet.pm,v 1.1172.2.93.4.3 2017/10/14 21:27:51 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -601,7 +601,7 @@ sub transfer_profile_to_env {
 
 # ---------------------------------------------------- Check for valid session 
 sub check_for_valid_session {
-    my ($r,$name,$userhashref) = @_;
+    my ($r,$name,$userhashref,$domref) = @_;
     my %cookies=CGI::Cookie->parse($r->header_in('Cookie'));
     if ($name eq '') {
         $name = 'lonID';
@@ -616,7 +616,16 @@ sub check_for_valid_session {
     } else {
         $lonidsdir=$r->dir_config('lonIDsDir');
     }
-    return undef if (!-e "$lonidsdir/$handle.id");
+    if (!-e "$lonidsdir/$handle.id") {
+        if ((ref($domref)) && ($name eq 'lonID') &&
+            ($handle =~ /^($match_username)\_\d+\_($match_domain)\_(.+)$/)) {
+            my ($possuname,$possudom,$possuhome) = ($1,$2,$3);
+            if ((&domain($possudom) ne '') && (&homeserver($possuname,$possudom) eq $possuhome)) {
+                $$domref = $possudom;
+            }
+        }
+        return undef;
+    }
 
     my $opened = open(my $idf,'+<',"$lonidsdir/$handle.id");
     return undef if (!$opened);
@@ -12812,8 +12821,23 @@ sub fetch_dns_checksums {
 	    my ($id,$domain,$role,$name,$protocol,$intdom)=split(/:/,$configline);
 	    $name=~s/\s//g;
 	    if ($id && $domain && $role && $name) {
+                if ((exists($hostname{$id})) && ($hostname{$id} ne '')) {
+                    my $curr = $hostname{$id};
+                    my $skip;
+                    if (ref($name_to_host{$curr}) eq 'ARRAY') {
+                        if (($curr eq $name) && (@{$name_to_host{$curr}} == 1)) {
+                            $skip = 1;
+                        } else {
+                            @{$name_to_host{$curr}} = grep { $_ ne $id } @{$name_to_host{$curr}};
+                        }
+                    }
+                    unless ($skip) {
+                        push(@{$name_to_host{$name}},$id);
+                    }
+                } else {
+                    push(@{$name_to_host{$name}},$id);
+                }
 		$hostname{$id}=$name;
-		push(@{$name_to_host{$name}}, $id);
 		$hostdom{$id}=$domain;
 		if ($role eq 'library') { $libserv{$id}=$name; }
                 if (defined($protocol)) {