1. ETH0--LAN
[Root @ server ~] # Cat/etc/sysconfig/network-scripts/ifcfg-eth0
Device = eth0
Hwaddr = 00: XX: 00: 97: xx
Onboot = Yes
Type = Ethernet
Bootproto = none
Ipaddr = 192.168.0.254
Netmask = 255.255.255.0
2. EHT1--WAN
[Root @ server ~] # Cat/etc/sysconfig/network-scripts/ifcfg-eth1
Device = eth1
Hwaddr = 00: XX: 00: 97: xx
Onboot = Yes
Bootproto = none
Type = Ethernet
Ipaddr = 58.240.xx.ip
Netmask = 255.255.255.255.240
Gateway = 58.240.xx.gw
3. sysctl
[Root @ server ~] # Cat/etc/sysctl. conf
# Kernel sysctl configuration file for Red Hat Linux
#
# For binary values, 0 is disabled, 1 is enabled. See sysctl (8) and
# Sysctl. conf (5) for more details.
# Controls IP packet forwarding
Net. ipv4.ip _ forward = 1
......
[Root @ server ~] # Sysctl-P
Net. ipv4.ip _ forward = 1
4. SNAT
[Root @ server ~] # Iptables-T Nat-A postrouting-s 192.168.0.0/24-O eth1-j snat -- To 58.240.xx.ip
Or
[Root @ server ~] # Iptables-T Nat-A postrouting-O eth1-J Masquerade
Save the SNAT Configuration:
[Root @ server ~] #/Etc/init. d/iptables save
[Root @ server ~] # Cat/etc/sysconfig/iptables
# Generated by iptables-save v1.4.7 on Fri Mar 30 14:10:34 2012
* Filter
: Input accept [19774: 1796237]
: Forward accept [2088: 205908]
: Output accept [4335: 25558058]
Commit
# Completed on Fri Mar 30 14:10:34 2012
# Generated by iptables-save v1.4.7 on Fri Mar 30 14:10:34 2012
* Nat
: Prerouting accept [152787: 30285172]
: Postrouting accept [4:236]
: Output accept [9: 586]
#-A postrouting-s 192.168.0.0/24-O eth1-j snat -- To 58.240.xx.ip
-A postrouting-O eth1-J Masquerade
Commit
# Completed on Fri Mar 30 14:10:34 2012
After finishing, close the job.