diff --git a/features/dsl_netns.feature b/features/dsl_netns.feature
new file mode 100644
index 0000000..5bdd1b8
--- /dev/null
+++ b/features/dsl_netns.feature
@@ -0,0 +1,84 @@
+Feature: The netns DSL directive.
+  @sudo
+  Scenario: phut run with "netns(alias) { ip ... }"
+    Given a file named "network.conf" with:
+    """
+    netns('host1') {
+      ip '192.168.8.6'
+    }
+    netns('host2') {
+      ip '192.168.8.7'
+    }
+    link 'host1', 'host2'    
+    """
+    When I do phut run "network.conf"
+    Then a netns named "host1" launches
+    And the "netmask" of the netns "host1" should be "/24"
+    And the "default_gateway" of the netns "host1" should be ""
+    And a netns named "host2" launches
+    And the "netmask" of the netns "host2" should be "/24"
+    And the "default_gateway" of the netns "host2" should be ""
+
+  @sudo
+  Scenario: phut run with "netns(alias) { ip, netmask, route ... }"
+    Given a file named "network.conf" with:
+    """
+    netns('host1') {
+      ip '192.168.8.6'
+      netmask '255.255.255.128'
+      route net: '0.0.0.0/0', gateway: '192.168.8.1'
+    }
+    netns('host2') {
+      ip '192.168.8.7'
+      netmask '255.255.255.128'
+      route net: '0.0.0.0/0', gateway: '192.168.8.1'
+    }
+    link 'host1', 'host2'    
+    """
+    When I do phut run "network.conf"
+    Then a netns named "host1" launches
+    And the "netmask" of the netns "host1" should be "/25"
+    And the "default_gateway" of the netns "host1" should be "192.168.8.1"
+    And a netns named "host2" launches
+    And the "netmask" of the netns "host2" should be "/25"
+    And the "default_gateway" of the netns "host2" should be "192.168.8.1"
+
+  @sudo
+  Scenario: phut run with "netns(alias) { ip, vlan }"
+    Given a file named "network.conf" with:
+    """
+    netns('host1') {
+      ip '192.168.8.6'
+      vlan 10
+    }
+    netns('host2') {
+      ip '192.168.8.7'
+      vlan 20
+    }
+    link 'host1', 'host2'
+    """
+    When I do phut run "network.conf"
+    Then a netns named "host1" launches
+    And the "vlan" of the netns "host1" should be "10"
+    And a netns named "host2" launches
+    And the "vlan" of the netns "host2" should be "20"
+
+  @sudo
+  Scenario: phut run with "netns(alias) { ip, mac }"
+    Given a file named "network.conf" with:
+    """
+    netns('host1') {
+      ip '192.168.8.6'
+      mac '00:53:00:00:00:01'
+    }
+    netns('host2') {
+      ip '192.168.8.7'
+      mac '00:53:00:00:00:02'
+    }
+    link 'host1', 'host2'
+    """
+    When I do phut run "network.conf"
+    Then a netns named "host1" launches
+    And the "mac" of the netns "host1" should be "00:53:00:00:00:01"
+    And a netns named "host2" launches
+    And the "mac" of the netns "host2" should be "00:53:00:00:00:02"
diff --git a/features/step_definitions/phut_steps.rb b/features/step_definitions/phut_steps.rb
index cd26eb2..13e745d 100644
--- a/features/step_definitions/phut_steps.rb
+++ b/features/step_definitions/phut_steps.rb
@@ -36,6 +36,28 @@
   step %(a file named "vhost.#{name}.pid" should exist)
 end
 
+Then(/^a netns named "(.*?)" launches$/) do |name|
+  expect(`ip netns`).to match(/^#{name}$/)
+end
+
+# rubocop:disable LineLength
+Then(/^the "(.*?)" of the netns "(.*?)" should be "(.*?)"$/) do |key, netns, value|
+  command =
+    case key
+    when 'netmask'
+      "ip addr list dev #{netns} | grep inet"
+    when 'default_gateway'
+      'ip route list match 0/0'
+    when 'vlan'
+      "ip link list dev #{netns}.#{value}"
+    else
+      'ip link list ; ip addr list'
+    end
+
+  expect(`sudo ip netns exec #{netns} #{command}`).to match(/#{value}/)
+end
+# rubocop:enable LineLength
+
 Then(/^a link is created between "(.*?)" and "(.*?)"$/) do |name_a, name_b|
   cd('.') do
     link = Phut::Parser.new.parse(@config_file).fetch([name_a, name_b].sort)
diff --git a/lib/phut/netns.rb b/lib/phut/netns.rb
index b9561d6..99a3ec1 100644
--- a/lib/phut/netns.rb
+++ b/lib/phut/netns.rb
@@ -26,19 +26,55 @@ def initialize(options, name, logger)
       @logger = logger
     end
 
-    # rubocop:disable AbcSize
     def run
+      setup_netns
+      setup_link
+      setup_ip
+    end
+
+    def stop
+      sh "sudo ip netns delete #{name}"
+    end
+
+    private
+
+    def setup_netns
       sh "sudo ip netns add #{name}"
       sh "sudo ip link set dev #{network_device} netns #{name}"
-      sh "sudo ip netns exec #{name} ifconfig lo 127.0.0.1"
+    end
+
+    def setup_link
+      setup_vlan
+      setup_mac_address
+      sh "sudo ip netns exec #{name} ip link set lo up"
       sh "sudo ip netns exec #{name}"\
-         " ifconfig #{network_device} #{ip} netmask #{netmask}"
-      sh "sudo ip netns exec #{name} route add -net #{net} gw #{gateway}"
+        " ip link set #{network_device}#{vlan_suffix} up"
     end
-    # rubocop:enable AbcSize
 
-    def stop
-      sh "sudo ip netns delete #{name}"
+    def setup_vlan
+      return unless vlan
+      sh "sudo ip netns exec #{name}"\
+        " ip link set #{network_device} up"
+      sh "sudo ip netns exec #{name}"\
+        " ip link add link #{network_device} name"\
+        " #{network_device}#{vlan_suffix} type vlan id #{vlan}"
+    end
+
+    def setup_mac_address
+      sh "sudo ip netns exec #{name}"\
+        " ip link set #{network_device}#{vlan_suffix} address #{mac}" if mac
+    end
+
+    def setup_ip
+      sh "sudo ip netns exec #{name} ip addr replace 127.0.0.1 dev lo"
+      sh "sudo ip netns exec #{name}"\
+        " ip addr replace #{ip}/#{netmask} dev #{network_device}#{vlan_suffix}"
+      sh "sudo ip netns exec #{name}"\
+        " ip route add #{net} via #{gateway}" if gateway
+    end
+
+    def vlan_suffix
+      vlan ? ".#{vlan}" : ''
     end
 
     def method_missing(message, *_args)
diff --git a/lib/phut/syntax/netns_directive.rb b/lib/phut/syntax/netns_directive.rb
index d32d17b..7a7c4dc 100644
--- a/lib/phut/syntax/netns_directive.rb
+++ b/lib/phut/syntax/netns_directive.rb
@@ -7,7 +7,13 @@ class NetnsDirective < Directive
       attribute :netmask
 
       def initialize(alias_name, &block)
-        @attributes = { name: alias_name }
+        @attributes =
+          { name: alias_name,
+            netmask: '255.255.255.0',
+            net: '0.0.0.0',
+            gateway: nil,
+            mac: nil,
+            vlan: nil }
         instance_eval(&block)
       end
 
@@ -20,6 +26,14 @@ def route(options)
         @attributes[:net] = options.fetch(:net)
         @attributes[:gateway] = options.fetch(:gateway)
       end
+
+      def mac(value)
+        @attributes[:mac] = value
+      end
+
+      def vlan(value)
+        @attributes[:vlan] = value
+      end
     end
   end
 end