--- doc/install/linux/install.pl	2023/04/28 19:33:48	1.83
+++ doc/install/linux/install.pl	2024/04/24 23:17:48	1.84
@@ -78,7 +78,7 @@ if (!open(LOG,">>loncapa_install.log"))
           &mt('Stopping execution.')."\n";
     exit;
 } else {
-    print LOG '$Id: install.pl,v 1.83 2023/04/28 19:33:48 raeburn Exp $'."\n";
+    print LOG '$Id: install.pl,v 1.84 2024/04/24 23:17:48 raeburn Exp $'."\n";
 }
 
 #
@@ -1700,14 +1700,30 @@ sub get_pathto_iptables {
 
 sub firewall_is_active {
     if (-e '/proc/net/ip_tables_names') {
+        my $status;
         if (open(PIPE,'cat /proc/net/ip_tables_names |grep filter |')) {
-            my $status = <PIPE>;
+            $status = <PIPE>;
             close(PIPE);
             chomp($status);
             if ($status eq 'filter') {
                 return 1;
             }
         }
+        unless ($status) {
+            if (open(PIPE,'nft list tables |')) {
+                while(<PIPE>) {
+                    chomp();
+                    if (/filter$/) {
+                        $status = 1;
+                        last;
+                    }
+                }
+                close(PIPE);
+                if ($status) {
+                    return 1;
+                }
+            }
+        }
     }
     return 0;
 }