Iptables - Revision history

Tom at 17:33, 17 September 2011

2011-09-17T17:33:18Z

Tom at 17:30, 17 September 2011

2011-09-17T17:30:52Z

Tom at 17:27, 17 September 2011

2011-09-17T17:27:31Z

Tom: Created page with "== Share Internet connection creating a NAT == Sometime it´s handy to share an Internet connection with other network devices. For example to dial in using an UMTS modem and the..."

2011-09-17T17:12:47Z

Created page with "== Share Internet connection creating a NAT == Sometime it´s handy to share an Internet connection with other network devices. For example to dial in using an UMTS modem and the..."

New page

== Share Internet connection creating a NAT ==
Sometime it´s handy to share an Internet connection with other network devices. For example to dial in using an UMTS modem and then getting a second computer (client) on the LAN port online.
*enable IP forwarding
*create a simple NAT
<nowiki>echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE</nowiki>
''ppp0'' is the network device with an Internet connection.
Important notes:
*the LAN port for the client´s network must have an IP address set
*clients must have an IP address within the same subnet of course
*clients must have a default route set
*clients should have a manual DNS server entry

@@ Line 13: / Line 13: @@
 Because that means a lot of work, here is a Shellscript that
-*configures the LAN port eth0
+*configures the LAN port ''eth0''
-*enables IP forwarding and sets up a nat for ppp0
+*enables IP forwarding and sets up a nat for ''ppp0''
 *launches ''dnsmasq'' as a DHCP and DNS server. Client´s get their IP address and DNS server address automatically assigned.
   <nowiki>#!/bin/sh

← Older revision		Revision as of 17:27, 17 September 2011
Line 11:		Line 11:
	*clients must have a default route set		*clients must have a default route set
	*clients should have a manual DNS server entry		*clients should have a manual DNS server entry
		+
		+	Because that means a lot of work, here is a Shellscript that
		+	*configures the LAN port eth0
		+	*enables IP forwarding and sets up a nat for ppp0
		+	*launches ''dnsmasq'' as a DHCP and DNS server. Client´s get their IP address and DNS server address automatically assigned.
		+	<nowiki>#!/bin/sh
		+	#Internet-Gateway für netzwerk auf eth0 einrichten.
		+	#Zugang ist ppp0
		+
		+	if [ "$1" = "start" ]; then
		+	echo Gateway erstellen ...
		+	#Interface einstellen
		+	ifconfig eth0 192.168.10.1 up
		+	#IP forwarding einschalten
		+	echo 1 > /proc/sys/net/ipv4/ip_forward
		+	#NAT
		+	iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
		+	#DNS und DHCP
		+	dnsmasq --dhcp-range=192.168.10.10,192.168.10.50,255.255.255.0,1h --no-dhcp-interface=ppp0 --log-dhcp --log-queries
		+
		+	elif [ "$1" = "stop" ]; then
		+	echo Gateway beenden ...
		+	#DNS und DHCP Server aus
		+	start-stop-daemon --stop --retry=TERM/30/KILL/5 --pidfile /var/run/dnsmasq.pid --name dnsmasq
		+	#IP forwarding aus
		+	echo 0 > /proc/sys/net/ipv4/ip_forward
		+	#NAT aus
		+	iptables -t nat -D POSTROUTING -o ppp0 -j MASQUERADE
		+	#Interface aus
		+	ifconfig eth0 down
		+
		+	else
		+	echo Internet-Gateway script
		+	echo Aufruf mit Parameter start oder stop!
		+	fi</nowiki>
		+	Make sure ''dnsmasq'' is installed. Change the network interfaces and the IP range according to your needs. The script is quite simple, don´t expect too much ;)
		+
		+	Run the internet gateway script as root with parameter ''start''.
		+	<nowiki>sudo ./inetgateway.sh start</nowiki>

@@ Line 1: / Line 1: @@
-== Share Internet connection creating a NAT ==
+== Share Internet connection ==
 Sometime it´s handy to share an Internet connection with other network devices. For example to dial in using an UMTS modem and then getting a second computer (client) on the LAN port online.
 *enable IP forwarding