jscanner

commit 76baa932a90a65c5666b6358af81a89bdc3ca47e
parent 8b9a77ec8c00a5a92e37678b98774b4f180ba38e
Author: Matthias Jaros <jaros@mailbox.org>
Date:   Mon, 23 Mar 2026 16:19:04 +0100

Added host online check

Diffstat:
M
src/main/java/com/it_jaros/network_scanner/CliDefaults.java
 | 
2
+-
M
src/main/java/com/it_jaros/network_scanner/Scanner.java
 | 
18
+++++++++++++++++-

2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/src/main/java/com/it_jaros/network_scanner/CliDefaults.java b/src/main/java/com/it_jaros/network_scanner/CliDefaults.java
@@ -5,7 +5,7 @@ public class CliDefaults {
     public static final int DELAY_IN_MILLIS = 0;
     public static final int TIMEOUT_IN_MILLIS = 300;
     public static final int MAX_WORKERS_PER_HOST = 1000;
-    public static final int MAX_TARGETS_LIMIT = 3;
+    public static final int MAX_TARGETS_LIMIT = 10;
     public static final String PORTS = "1-1024";
     public static final boolean SHOW_FILTERED_PORTS = false;
 }
diff --git a/src/main/java/com/it_jaros/network_scanner/Scanner.java b/src/main/java/com/it_jaros/network_scanner/Scanner.java
@@ -76,9 +76,15 @@ public class Scanner {
         BitSet openPorts = new BitSet(PortRange.MAX_PORT);
         BitSet filteredPorts = new BitSet(PortRange.MAX_PORT);
 
-        Progress progress = new Progress(target, portRange.getTotal(), new AtomicInteger(), new AtomicInteger(), new AtomicInteger() );
+        Progress progress = new Progress(target, portRange.getTotal(), new AtomicInteger(), new AtomicInteger(), new AtomicInteger());
         progressBar.submit(progress);
 
+        if(!checkHostOnline(target)) {
+            // Visually show that this host is basically done
+            progress.done().set(progress.total());
+            return new ScanResult(target, openPorts, filteredPorts);
+        }
+
         try (ExecutorService executor = Executors.newVirtualThreadPerTaskExecutor()) {
             List<Future<PortResult>> futures = new ArrayList<>();
             while (portRange.hasNext()) {
@@ -127,6 +133,16 @@ public class Scanner {
         return new ScanResult(target, openPorts, filteredPorts);
     }
 
+    private boolean checkHostOnline(String target) {
+        try {
+            return InetAddress.getByName(target).isReachable(2000);
+        } catch (IOException e) {
+            // something went wrong
+        }
+
+        return false;
+    }
+
     private void waitForSlot(AtomicLong scanSlotFactory) {
         if (delayInNanos > 0) {
             long slot = scanSlotFactory.getAndAdd(delayInNanos);