diff --git a/src/main.cr b/src/main.cr
index 23a9fe7..ef94dd7 100644
--- a/src/main.cr
+++ b/src/main.cr
@@ -61,8 +61,10 @@ OptionParser.parse! do |parser|
 		case command
 		when /^(list)/
 			STDERR.puts "TODO: list" unless arg.empty?
-		when /^(connect)/
-			STDERR.puts "TODO: connect" unless arg.empty?
+		when /^(up)/
+			STDERR.puts "TODO: up" unless arg.empty?
+		when /^(down)/
+			STDERR.puts "TODO: down" unless arg.empty?
 		else
 			STDERR.puts "Command #{command} not understood"
 		end
@@ -112,7 +114,7 @@ class NetworkCommands
 
 	class IWCommand
 		def self.get_ssid(ifname : String, ssid)
-			unless Do.run(cmd, [ name ]).success?
+			unless Do.run(cmd, [ ifname ]).success?
 				raise "(#{cmd}) dhcp failed on #{ifname}"
 			end
 		end
@@ -120,20 +122,16 @@ class NetworkCommands
 
 	class UDHCPCCommand
 		def self.run(ifname : String)
-			# TODO: verify which dhcp client is installed on the system
-			cmd = "udhcpc"
-			unless Do.run(cmd, [ name ]).success?
-				raise "(#{cmd}) dhcp failed on #{ifname}"
+			unless Do.run("udhcpc", [ ifname ]).success?
+				raise "(udhcpc) dhcp failed on #{ifname}"
 			end
 		end
 	end
 
 	class DHClientCommand
 		def self.run(ifname : String)
-			# TODO: verify which dhcp client is installed on the system
-			cmd = "udhcpc"
-			unless Do.run(cmd, [ name ]).success?
-				raise "(#{cmd}) dhcp failed on #{ifname}"
+			unless Do.run("dhclient", [ ifname ]).success?
+				raise "(dhclient) dhcp failed on #{ifname}"
 			end
 		end
 	end
@@ -156,7 +154,7 @@ class NetworkCommands
 		end
 
 		def self.set_ip(name : String, ip : IPAddress)
-			unless Do.run("ifconfig", [ name, "add", ip.to_string ]).success?
+			unless Do.run("ifconfig", [ name, ip.to_string ]).success?
 				raise "(ifconfig) Cannot set ip address #{ip.to_string} for #{name}"
 			end
 		end
@@ -164,8 +162,8 @@ class NetworkCommands
 		# currently, aliasses with ifconfig: ifconfig add ip/mask
 		# same command as the ip setup
 		def self.set_alias(name : String, ip : IPAddress)
-			unless Do.run("ifconfig", [ name, "add", ip.to_string ]).success?
-				raise "(ifconfig) Cannot set ip address alias #{ip.to_string} for #{name}"
+			unless Do.run("ifconfig", [ name, "add", ip.to_s ]).success?
+				raise "(ifconfig) Cannot set ip address alias #{ip.to_s} for #{name}"
 			end
 		end
 
@@ -180,6 +178,18 @@ class NetworkCommands
 				raise "(ifconfig) Cannot set description #{description} for #{name}"
 			end
 		end
+
+		def self.flush(name : String)
+			unless Do.run("ifconfig", [ name, "0.0.0.0" ]).success?
+				raise "(ifconfig) Cannot flush #{name} ip addresses"
+			end
+		end
+
+		def self.down(name : String)
+			unless Do.run("ifconfig", [ name, "down" ]).success?
+				raise "(ifconfig) Cannot set down #{name}"
+			end
+		end
 	end
 
 	class IPCommand
@@ -217,6 +227,18 @@ class NetworkCommands
 			end
 		end
 
+		def self.flush(name : String)
+			unless Do.run("ip", [ "address", "flush", "dev", name ]).success?
+				raise "(ip) Cannot flush #{name} ip addresses"
+			end
+		end
+
+		def self.down(name : String)
+			unless Do.run("ip", [ "link", "set", "down", "dev", name ]).success?
+				raise "(ip) Cannot set down #{name}"
+			end
+		end
+
 		def self.description(name : String, description : String)
 			puts "TODO: (ip) setup description '#{description}' to interface #{name}"
 			# unless Do.run("ip", [ "link", "set", "description", description, "dev", name ]).success?
@@ -244,9 +266,9 @@ class NetworkCommands
 	def self.dhcp(name : String)
 		cmd = @@cmd_dhcp_client
 		case cmd
-		when NotSetup
+		when NotSetup.class
 			puts "no dhcp client: cannot perform dhcp on #{name}"
-		when UDHCPCCommand
+		else
 			cmd.run name
 		end
 	end
@@ -263,12 +285,20 @@ class NetworkCommands
 		@@cmd_network_configuration.description name, description
 	end
 
+	def self.flush(name : String)
+		@@cmd_network_configuration.flush name
+	end
+
+	def self.down(name : String)
+		@@cmd_network_configuration.down name
+	end
+
 	def self.wireless_list_ssid(ifname : String)
 		cmd = @@cmd_wireless_configuration
 		case cmd
-		when NotSetup
+		when NotSetup.class
 			puts "no wireless configuration program: cannot list ssid"
-		when IWCommand
+		when IWCommand.class
 			cmd.list_ssid ifname
 		end
 	end
@@ -276,9 +306,9 @@ class NetworkCommands
 	def self.wireless_connect_wpa_psk(ifname : String, ssid : String, passwd : String)
 		cmd = @@cmd_wireless_configuration
 		case cmd
-		when NotSetup
+		when NotSetup.class
 			puts "no wireless configuration program: cannot connect to ssid #{ssid}"
-		when IWCommand
+		when IWCommand.class
 			cmd.list_ssid ifname
 		end
 	end
@@ -489,7 +519,7 @@ class InterfaceConfiguration
 			when DHCP
 				NetworkCommands.dhcp name
 			when NotSetup
-				puts "no ipv4"
+				# do nothing
 			else
 				raise "ipv4 configuration: neither static nor dynamic"
 			end
@@ -514,7 +544,7 @@ class InterfaceConfiguration
 			#when DHCP
 			#	NetworkCommands.dhcp6 name
 			when NotSetup
-				puts "no ipv6"
+				# do nothing
 			else
 				raise "ipv4 configuration: neither static nor dynamic"
 			end
@@ -527,6 +557,15 @@ class InterfaceConfiguration
 			end
 		end
 	end
+
+	def down
+		unless NetworkCommands.interface_exists(@name)
+			raise "The interface #{@name} doesn't exists or is already down."
+		end
+
+		NetworkCommands.flush name
+		NetworkCommands.down name
+	end
 end
 
 class NetworkConfigurationParser
@@ -807,8 +846,12 @@ case command
 when "list"
 	# TODO: why having to force "not_nil!" ? Seems like a compiler bug
 	puts NetworkConfigurationParser.parse_file(file.not_nil!)
-when "connect"
+when "up"
 	# TODO: why having to force "not_nil!" ? Seems like a compiler bug
 	network_configuration = NetworkConfigurationParser.parse_file(file.not_nil!)
 	network_configuration.execute
+when "down"
+	# TODO: why having to force "not_nil!" ? Seems like a compiler bug
+	network_configuration = NetworkConfigurationParser.parse_file(file.not_nil!)
+	network_configuration.down
 end