NAT Linux - Revision history

Heth: /* WEB server on the inside network */

2013-12-11T14:25:03Z

‎WEB server on the inside network

Heth: /* When you have a floating address on the external Interface */

2012-01-25T13:49:53Z

‎When you have a floating address on the external Interface

Heth: /* WEB server on the inside network */

2009-03-08T05:36:22Z

‎WEB server on the inside network

Heth at 15:50, 7 March 2009

2009-03-07T15:50:17Z

Heth at 11:02, 7 March 2009

2009-03-07T11:02:02Z

Heth at 11:01, 7 March 2009

2009-03-07T11:01:18Z

Heth: /* OLD */

2009-03-07T11:01:01Z

‎OLD

Heth at 11:00, 7 March 2009

2009-03-07T11:00:17Z

Heth: /* Basic NAT example using IP Tables */

2009-03-07T10:56:13Z

‎Basic NAT example using IP Tables

Heth: /* Checking IP Tables NAT rules and traffic */

2009-03-07T10:47:55Z

‎Checking IP Tables NAT rules and traffic

@@ Line 67: / Line 67: @@
 iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 443 -j DNAT --to 192.168.1.30:443
 </pre>
+==IP destination nat Forwarding with source nat==
 [[Category:Linux]]

@@ Line 24: / Line 24: @@
 Add the following lines to '''/etc/rc.local'''
 <pre>
-#  Enable IP Forwading between Interfaces (Routing)
+#  Enable IP Forwarding between Interfaces (Routing)
 echo "1" > /proc/sys/net/ipv4/ip_forward
 # Use iptables Source NAT (SNAT) to translate internal 192.168.1.0/24 IP addresses to the external IP Address that eth0 has
@@ Line 30: / Line 30: @@
 iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -d 0.0.0.0/0 -o eth1 -j MASQUERADE
 </pre>
 === Checking iptables NAT rules and traffic ===
 The [[iptables]] list option can be used to see [[iptables]] rules and [[iptables]] traffic.

@@ Line 64: / Line 64: @@
 <pre>
 iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 80 -j DNAT --to 192.168.1.30:80
 </pre>
 [[Category:Linux]]

@@ Line 1: / Line 1: @@
 {{TOCright}}
-IP Tables is used for packet filtering and NAT/PAT translation on several Linux distributions including
+[[iptables]] is used for packet filtering and NAT/PAT translation on several Linux distributions including
 *Ubunto
 *Redhat
 *Centos
-== Basic NAT example using IP Tables ==
+== Basic NAT example using iptables ==
-IPTABLES can be configured in two different ways when you boot your machine. The examples will assume you have two Network interface cards. '''eth0''' connected to the internal - private network - and '''eth1''' connected to the external - Internet.
+[[iptables]] can be configured in two different ways when you boot your machine. The examples will assume you have two Network interface cards. '''eth0''' connected to the internal - private network - and '''eth1''' connected to the external - Internet.
 *Using a startup script. Example below.
-*Using IPTABLES save and restore facelity. Example below.
+*Using [[iptables]] save and restore facelity. Example below.
 [[Image:Linux_nat_1.png‎|none|500px|thumb|Example network]]
-=== Using a startup script to configure IPTABLES ===
+=== Using a startup script to configure iptables ===
 ==== When you have a fixed address on the external Interface ====
 When you know your address on the external Interface - not using DHCP - you should use source NAT (SNAT), which is slightly more efficient than using masquerading.<br>
@@ Line 30: / Line 30: @@
 iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -d 0.0.0.0/0 -o eth1 -j MASQUERADE
 </pre>
-=== Checking IP Tables NAT rules and traffic ===
+=== Checking iptables NAT rules and traffic ===
-The IPTABLES list option can be used to see IPTABLES rules and IPTABLES traffic.
+The [[iptables]] list option can be used to see [[iptables]] rules and [[iptables]] traffic.
-use the command ''iptables -L -t nat'' to see the rules in the IPTABLES NAT chains.
+use the command ''iptables -L -t nat'' to see the rules in the [[iptables]] NAT chains.
 <pre>
 [root@bkshost etc]# iptables -L -t nat
@@ Line 46: / Line 46: @@
 target     prot opt source               destination
 </pre>
-use the command ''iptables -L -t nat '''-v''''' to see the rules in the IPTABLES chains and the traffic for each rule.
+use the command ''iptables -L -t nat '''-v''''' to see the rules in the [[iptables]] chains and the traffic for each rule.
 <pre>
 [root@bkshost etc]# iptables -L -t nat -v

← Older revision		Revision as of 11:02, 7 March 2009
Line 1:		Line 1:
		+	{{TOCright}}
	IP Tables is used for packet filtering and NAT/PAT translation on several Linux distributions including		IP Tables is used for packet filtering and NAT/PAT translation on several Linux distributions including
	*Ubunto		*Ubunto

← Older revision		Revision as of 11:01, 7 March 2009
Line 1:		Line 1:
−	~~= NEW =~~
	IP Tables is used for packet filtering and NAT/PAT translation on several Linux distributions including		IP Tables is used for packet filtering and NAT/PAT translation on several Linux distributions including
	*Ubunto		*Ubunto

← Older revision		Revision as of 11:01, 7 March 2009
Line 66:		Line 66:
	</pre>		</pre>

−	~~=OLD=~~
−	~~Add the following lines to '''/etc/rc.local''' to configure Routing at boot.~~
−	~~=== Using IPTABLES-SAVE/RESTORE to configure IPTABLES ===~~
−	~~== Enable IP Forwarding (Routing) between interfaces ==~~
−	~~Before you can route packets from the Inside network Interface to the outside network Interface, you need to enable IP forwarding.~~
−	~~=== Enabling forwarding until next boot ===~~
−	~~To enable IP forwarding you need to toggle a switch in the kernel, you can do that with the following command. But remember, next time you boot the machine, it will be switched of again.~~
−	~~<pre>~~
−	~~echo "1" > /proc/sys/net/ipv4/ip_forward~~
−	~~</pre>~~
−	~~=== Enable IP forwarding permanently ===~~
−	~~To enable IP forwarding permanently, you either need to issue the command below in a boot-script. '''/etc/rc.local''' or similar<br/>~~
−	~~or<br/>~~
−	~~Change the file '''/etc/sysctl.conf''' to include the following line. Perhaps you only need to uncomment a line. (Remove the # from beginning of the line)~~
−	~~<pre>~~
−	~~net.ipv4.ip_forward=1~~
−	~~</pre>~~
−	~~Note that altering '''/etc/sysctl.conf''' will first be effective after reboot.~~
−
−	~~== Basic NAT example using IP Tables ==~~
−	In the example below the internal network 192.168.1.0/24 is Source Natted (SNAT) to the external IP Address 83.90.47.30. Source nat also makes port translations. So the example uses NAT/PAT, and would be sufficient as a NAT/PAT solution for a private network.<br/>
−
−	~~<pre>~~
−	~~iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -d 0.0.0.0/0 -j SNAT --to 83.90.47.30~~
−	~~</pre>~~
−	~~use the command ''iptables -L -t nat'' to see the rule in the IPTABLES chains.~~
−	~~<pre>~~
−	~~[root@bkshost etc]# iptables -L -t nat~~
−	~~Chain PREROUTING (policy ACCEPT)~~
−	~~target prot opt source destination~~
−
−	~~Chain POSTROUTING (policy ACCEPT)~~
−	~~target prot opt source destination~~
−	~~SNAT all -- 192.168.1.0/24 anywhere to:83.90.47.30~~
−
−	~~Chain OUTPUT (policy ACCEPT)~~
−	~~target prot opt source destination~~
−	~~</pre>~~
−	~~=== Webserver located on internal network ===~~
−	~~To redirect WEB traffic originating from the outside to a WEB-server on the inside you would use a rule as showed below.~~
−	~~<pre>~~
	[[Category:Linux]]		[[Category:Linux]]

@@ Line 61: / Line 61: @@
 === WEB server on the inside network ===
 If you have a WEB server on the inside network for example 192.168.1.30, which should be accessible from the outside. (eth1)
 <pre>
 iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 80 -j DNAT --to 192.168.1.30:80

@@ Line 57: / Line 57: @@
 Chain OUTPUT (policy ACCEPT 15307 packets, 1758K bytes)
   pkts bytes target     prot opt in     out     source               destination
 </pre>