Difference between revisions of "Set up Network Address Translation"
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= Overview = | = 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. | 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. | ||
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| + | ----------------------------------------------------------- | ||
| + | | | | ||
| + | | | | ||
| + | --------- ------------- -------------- | | ||
| + | |internet |------------| NAT-gateway |------------------| internal | | | ||
| + | --------- | 10.2.2.18 | | 172.16.0.42 | | | ||
| + | ------------- -------------- | | ||
| + | | | | ||
| + | ----------------------------------------------------------- | ||
= Set it up = | = Set it up = | ||
Revision as of 10:37, 19 July 2012
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.
-----------------------------------------------------------
| |
| |
--------- ------------- -------------- |
|internet |------------| NAT-gateway |------------------| internal | |
--------- | 10.2.2.18 | | 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
