How to bind an IPv4 address to Apache Tomcat in CentOS/RHEL

How to bind an IPv4 address to Apache Tomcat in CentOS/RHEL

Today, we will learn how to bind IPv4 to Tomcat in CentOS 7 Linux distributed system.

Apache Tomcat is an open source web server and servlet Container developed by the Apache Software Foundation. It implements Java Servlet, JavaServer Page (JSP), Java's Unified Expression Language, and Sun Microsystems's Java WebSocket specification, and provides a web server environment for running java code.

If our web server cannot work properly because tomcat is bound to IPv6 by default, it is necessary to bind tomcat to IPv4. As we all know, IPv6 is a modern method for assigning IP addresses to devices. Although it may be applied in the near future, it has not been fully applied yet. Because it is useless, we do not need to convert our Tomcat server to IPv6. we should bind it to IPv4.

Before binding tomcat to IPv4, make sure that tomcat is installed in CentOS 7. You can refer to the instructions for installing Tomcat in CentOS 6.5.

 

1. Switch to the tomcat user

First, we need to switch to the tomcat user. You can run the su tomcat command in shell or terminal.

# su tomcat

 

2. Find the file Catalina. sh.

Now we want to go to the bin folder under the Apache Tomcat installation directory, usually/usr/share/apache-tomcat-8.0.x/bin/, where x is the sub version of the Apache Tomcat release. Because the version installed on my CentOS 7 server is 8.0.18, my directory is/usr/share/apache-tomcat-8.0.18/bin /.

$ cd /usr/share/apache-tomcat-8.0.18/bin

Note: replace 8.0.18 with the version number of Apache Tomcat installed in your system.

In the bin directory, there is a script file named catalina. sh. This is the file we want to edit. We will add a line in it to bind tomcat to IPv4 configuration information. You can run the ls command in shell or terminal to view the file.

$ ls

 

3. Configure Catalina. sh

, We will add a line at the end of the catalina. sh script fileJAVA_OPTS= "$JAVA_OPTS -Djava.net.preferIPv4Stack=true -Djava.net.preferIPv4Addresses". We can use our favorite text editor to edit this file, such as nano and vim. Here we use nano.

$ nano catalina.sh

Then, add the row to the file, as shown in.

Now, we have added the configuration information to the file. Save the file and exit nano.

 

4. Restart

Now, we restart the tomcat server to make the configuration take effect. Run shutdown. sh and startup. sh.

$ ./shutdown.sh

Run the executable file startup. sh:

$ ./startup.sh

This will restart our tomcat server and load the configuration information for binding the server to IPv4.

 

End

Now, we finally bound the tomcat server running on CentOS 7 Linux to IPv4. Although IPv6 may be applied in the near future, it is not used yet. If your Tomcat server is bound to IPv6, your tomcat server will not work, it is necessary to bind tomcat to IPv4, which is also very simple. If you have any questions, suggestions, and feedback, please write them down in the comment box below to let us know what needs to be added or improved. Thank you very much!

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