（转载）iptables 转发oracle端口

本文出自 “乡丅亻” 博客，请务必保留此出处http://shaowu.blog.51cto.com/627407/514909

项目组同事需要将SQL请求转发到另一台服务器上，于是通过iptables实现此功能

[root@gea-1 ~]# echo 1 > proc/sys/net/ipv4/ip_forward
[root@gea-1 ~]# iptables -t nat -A PREROUTING -d 192.168.18.19 -p tcp --dport 1521 -j DNAT --to 192.168.4.74:1521
[root@gea-1 ~]# iptables -t nat -A POSTROUTING -d 192.168.4.74 -p tcp --dport 1521 -j SNAT --to 192.168.18.19

查看nat 规则：

[root@gea-1 ~]# iptables -L -n -t nat
Chain PREROUTING (policy ACCEPT)
target     prot opt source               destination
DNAT       tcp  --  0.0.0.0/0            192.168.18.19        tcp dpt:1521 to:192.168.4.74:1521

Chain POSTROUTING (policy ACCEPT)
target     prot opt source               destination
SNAT       tcp  --  0.0.0.0/0            192.168.4.74       tcp dpt:1521 to:192.168.18.19

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination

Telnet测试：

[root@gea-1 ~]# telnet 192.168.4.74 1521
Trying 192.168.4.74...
Connected to localhost (192.168.4.74).
Escape character is '^]'.

保存iptables设置：

[root@gea-1 ~]# iptables-save >> /etc/sysconfig/iptables