There are three machines, A, B, and C. Machine A has Internet and Intranet IP addresses, and machine B and C only have Intranet. We configure machine B and machine C to access the Internet through machine.
Assume that the Internet IP address of machine A is: 60.12.13.14 and the Intranet IP address is 192.168.0.1.
Host B IP Address: 192.168.0.2
The IP address of machine C is 192.168.0.3.
On machines B and C, we configure the NIC configuration file and add machine A as the gateway.
Modify
- VI/etc/sysconfig/network-scripts/ifcfg-eth1
Add:
- Gateway = 192.168.0.1
Then restart the network of the two machines.
- /Etc/init. d/network restart
Modify the DNS configuration file of the two machines and add the same DNS as machine.
- VI/etc/resolv. conf
Add:
- Nameserver 202.99.96.68 # modify DNS based on your server
Save it.
We configure iptables on machine A and add SNAT
CD/usr/local/sbin/
VI iptables. Sh
- #! /Bin/sh
- Iptables-T nat-I postrouting-s 192.168.0.0/24-J SNAT -- to-source 60.12.13.14
- Iptables-a forward-s 192.168.0.0/24-J accept
- Iptables-a forward-D 192.168.0.0/24-J accept
- /Etc/init. d/iptables save
Run scripts
- Sh iptables. Sh
In this way, the content in the iptables. Sh script is saved
- /Etc/sysconfig/iptables
File.
On Machine A, set iptbals to boot.
- Chkconfig -- level 345 iptables on
On Machine A, enable the IP forwarding function and modify the sysctl. conf file.
- VI/etc/sysctl. conf
Set
- Net. ipv4.ip _ forward = 0
To:
- Net. ipv4.ip _ forward = 1
Then execute:
- Sysctl-P
Make it take effect.
After everything is ready, you can access the Internet on machines B and C, for example, ping the external IP address and domain name.
You can easily use Yum to update and download the software ..
Note:
During the operation, I first performed operations on machines A and B. When B can access the Internet, I found that machine A cannot connect to machine C, later, I thought there was a problem with machine C, so I didn't try to connect machine B to machine C. After that, we notified the data center to restart and found that there was still no way to connect to C through a. After that, there was no way to connect A to C through the local physical machine after the data center was connected to the monitor, however, IDC engineers tried to connect to C through B and found that it was caused by adjusting the Intranet access without adding a gateway. After connecting B to C, add the gateway and restart the NIC, A can connect to C, and C can also access the internet. After a while, let's make a souvenir. More attempts
How to configure an intranet server for IDC to access the Internet through iptables SNAT
