--- loncom/lonnet/perl/lonnet.pm	2005/09/01 05:07:35	1.652
+++ loncom/lonnet/perl/lonnet.pm	2005/09/01 06:47:26	1.654
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.652 2005/09/01 05:07:35 albertel Exp $
+# $Id: lonnet.pm,v 1.654 2005/09/01 06:47:26 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -5896,14 +5896,21 @@ BEGIN {
 
 sub get_iphost {
     if (%iphost) { return %iphost; }
+    my %name_to_ip;
     foreach my $id (keys(%hostname)) {
 	my $name=$hostname{$id};
-	my $ip = gethostbyname($name);
-	if (!$ip || length($ip) ne 4) {
-	    &logthis("Skipping host $id name $name no IP found\n");
-	    next;
+	my $ip;
+	if (!exists($name_to_ip{$name})) {
+	    $ip = gethostbyname($name);
+	    if (!$ip || length($ip) ne 4) {
+		&logthis("Skipping host $id name $name no IP found\n");
+		next;
+	    }
+	    $ip=inet_ntoa($ip);
+	    $name_to_ip{$name} = $ip;
+	} else {
+	    $ip = $name_to_ip{$name};
 	}
-	$ip=inet_ntoa($ip);
 	push(@{$iphost{$ip}},$id);
     }
     return %iphost;