Shulou(Shulou.com)06/01 Report--

This article mainly introduces how to configure port forwarding under CentOS, which has a certain reference value. Interested friends can refer to it. I hope you will learn a lot after reading this article. Let's take a look at it.

Enable IP forwarding

First, enable the IP forwarding function, which is disabled by default.

Temporary modification:

# echo 1 > / proc/sys/net/ipv4/ip_forward

It takes effect immediately after the modification, but reverts to the default value of 0 if the system is rebooted.

Permanent modification:

Vi / etc/sysctl.conf

# find the following value and change 0 to 1

Net.ipv4.ip_forward = 1

# sysctl-p (make it effective immediately)

The default value of 0 is to disable ip forwarding. If you change it to 1, you can enable ip forwarding.

Configure port forwarding

Suppose that when a user accesses 172.16.4.247VR 728, I want it to be forwarded to 172.16.4.97VR 80:

# iptables-t nat-A PREROUTING-p tcp-d 113.108.110.61-- dport 728-j DNAT-- to-destination 172.16.4.97 tcp 80

# iptables-t nat-A POSTROUTING-p tcp-s 172.16.4.97-- sport 80-j SNAT-- to-source 172.16.4.247

# service iptables save (save the current rule to / etc/sysconfig/iptables)

Alternatively, you can modify the / etc/sysconfig/iptables file directly:

-A PREROUTING-d 172.16.4.247 tcp 32-p tcp-m DNAT-- dport 728-j DNAT-- to-destination 172.16.4.97 Vor80

-A POSTROUTING-s 172.16.4.97 tcp 32-p tcp-m tcp-- sport 80-j SNAT-- to-source 172.16.4.247

Finally, don't forget to open port 728.

-An INPUT-p tcp-m state-- state NEW-m tcp-- dport 728-j ACCEPT

After the configuration is complete, remember to restart the firewall:

# service iptables restart

Native port forwarding

If you only need to forward between different ports of this machine, it will be easier. For example, to access http://ip:729, I want to return the content of http://ip:80. The configuration is as follows:

[root@localhost sbin] # iptables-t nat-A PREROUTING-p tcp-- dport 729-j REDIRECT-- to-ports 80

[root@localhost sbin] # service iptables save

[root@localhost sbin] # service iptables restart

Thank you for reading this article carefully. I hope the article "how to configure Port forwarding under CentOS" shared by the editor will be helpful to everyone. At the same time, I also hope you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.