Rinetd, the simplest port forwarding tool under Linux, implements port forwarding

stay Linux In most cases, the system chooses to use iptables To achieve port forwarding ,iptables Although powerful , But the configuration is inconvenient , And novices are prone to mistakes . Share another TCP/UDP Port forwarding tool rinetd,rinetd Small size , The configuration is also very simple .

This article uses CentOS 7 For example , Copy the following command input , A line of one ：

install rinetd
1, Installation dependency

yum -y install gcc gcc-c++ make

2, download rinetd

wget https://github.com/samhocevar/rinetd/releases/download/v0.70/rinetd-0.70.tar.gz

3, decompression

tar xf rinetd-0.70.tar.gz

4, Entry directory

cd rinetd-0.70

5, Compilation and installation

./bootstrap
./configure
make && make install

6, After installation , You can enter rinetd -v Check out the current version .

[root@localhost rinetd-0.70]# rinetd -v
rinetd 0.70

Configure forwarding
1, edit rinetd The configuration file

vi /usr/local/etc/rinetd.conf

2, Fill in the following

0.0.0.0 8080 1.1.1.1 80

3, start-up rinetd

rinetd -c /usr/local/etc/rinetd.conf

4, Configuration parameter description
0.0.0.0： Source IP It's local monitoring IP
8080： Source port
1.1.1.1： The goal is IP, For the convenience of memory, you can use domain name instead of , But if the domain name is on this computer ping It will fail to start
80： Target port

establish systemd service

1, establish rinetd service

vi /etc/systemd/system/rinetd.service

Copy the following content to save ：

[Unit]
Description=rinetd
After=network.target
[Service]
Type=forking
ExecStart=/usr/local/sbin/rinetd -c /usr/local/etc/rinetd.conf
ExecReload=/bin/kill -SIGHUP $MAINPID
ExecStop=/bin/kill -SIGINT $MAINPID
[Install]
WantedBy=multi-user.target

2, Enter the command ：systemctl daemon-reload heavy load daemon Make it effective , Then you can use the following command to manage rinetd 了 .
# start-up rinetd

systemctl start rinetd

# Set boot up

systemctl enable rinetd

# stop it rinetd

systemctl stop rinetd

# restart

systemctl restart rinetd

# close

killall rinetd

Check that the number of connections to the machine is not high

 ss -s

Check port usage

netstat -antup