Difference between revisions of "Set up Network Address Translation"
From Linuxintro
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= See also = | = See also = | ||
* [[set up a wireless accesspoint]] | * [[set up a wireless accesspoint]] | ||
| + | * [[Tunneling with OpenSSH]] | ||
* [http://www.nerdgrind.com/set-up-nat-with-linux-and-iptables-firewall/ set up NAT] | * [http://www.nerdgrind.com/set-up-nat-with-linux-and-iptables-firewall/ set up NAT] | ||
[[Category:Guides]] | [[Category:Guides]] | ||
Revision as of 12:16, 24 December 2013
Contents
Overview
Network address translation (NAT) is if you have a private network with private IP addresses and all these computers share access the internet via one computer. This computer, it can also be a cluster, is said to translate the network addresses between the private network and the internet.
-----------------------------------------------------------
| |
| -------------- |
| | internal | |
| /| 172.16.0.43 | |
| / -------------- |
------------- / |
--------- | NAT-gateway | / -------------- |
|internet |------------| 10.2.2.18 | / | internal | |
--------- | 172.16.0.1 |------------------| 172.16.0.42 | |
------------- -------------- |
| |
-----------------------------------------------------------
Set it up
To set up NAT (network address translation), open a console and
- allow IP traffic forwarding
echo 1 > /proc/sys/net/ipv4/ip_forward
- tell the kernel to forward traffic to the outgoing interface eth0 and masquerade it, so it will put its own IP address into each packet's header:
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
Test it
To test if it has worked, go to one of the internal computers and set the computer doing NAT as gateway, e.g. under Linux:
route add default gw 192.168.0.1
Then try to ping google's name server. If it works, you did it right:
ping 8.8.8.8
