diff --git a/src/cli/portscan_cli.cpp b/src/cli/portscan_cli.cpp
index 0e637b2..2eefe57 100644
--- a/src/cli/portscan_cli.cpp
+++ b/src/cli/portscan_cli.cpp
@@ -4,7 +4,6 @@
 
 PortScanCli::PortScanCli()
     : CliBase("Port Scanner Options")
-    , ip_("")
 {
 }
 
@@ -12,15 +11,18 @@ void PortScanCli::setupOptions()
 {
     // clang-format off
     desc_.add_options()
-        ("help,h",     "Show help")
-        ("ip,H",       withDefault(ip_, "<IP>"),    "Local IPv4 to scan");
+        ("help,h",      "Show help")
+        ("ip,H",        withDefault(ip_, "<IPv4>"),      "Base IPv4 inside your LAN (e.g. 10.0.1.42)")
+        ("prefix,p",    withDefault(prefix_, "<0..32>"), "CIDR prefix length (e.g. 24)");
     // clang-format on
 }
 
-std::string PortScanCli::getIp() const
+int PortScanCli::getPrefix() const
+{
+    return vm_.at("prefix").as<int>();
+}
+
+std::string PortScanCli::getBaseIp() const
 {
-    if (vm_["ip"].empty() == 0) {
-        return "127.0.0.1";
-    }
     return vm_.at("ip").as<std::string>();
 }
diff --git a/src/cli/portscan_cli.hpp b/src/cli/portscan_cli.hpp
index bf12444..5b5412f 100644
--- a/src/cli/portscan_cli.hpp
+++ b/src/cli/portscan_cli.hpp
@@ -9,11 +9,13 @@ class PortScanCli : public CliBase, protected OptionUtils
   public:
     PortScanCli();
 
-    std::string getIp() const;
+    int getPrefix() const;
+    std::string getBaseIp() const;
 
   protected:
     void setupOptions() override;
 
   private:
-    std::string ip_;
+    int prefix_{24};
+    std::string ip_{"10.0.1.0"};
 };