DEV Community


Posted on

what is ip address?

Have you ever seen the address and wondered what it means?

This is a special IP address that represents all interfaces on a machine. In this blog post, we will discuss what the address is used for and how to interpret it!

What is ip address? is a special IP address known as the "default route" or "unspecified address". It is used to indicate that traffic should be sent to all interfaces on a machine, regardless of their individual IP addresses.

This can be useful in certain networking scenarios, such as when you want to send traffic to multiple devices on a single network.

For example: if you have a server with two network interfaces – one connected to a local network and the other connected to the internet.

If you want the SSH service running on both networks, you could use as the source address. This would allow the server to accept SSH connections from both networks. is also widely used in the network access control list. The ACL is used to allow or deny traffic from specific IP addresses or ranges of IP addresses.

For example, you can create an ACL that allows all traffic from the address range, which is effectively the same as allowing traffic from all IP addresses.

It's important to note that isn't a real IP address and can't be used for communication; it's simply an identifier used in network configurations. ip address in netstat command

When you use the netstat command, will generally appear as the source or destination address for certain connections. For example, if you want to see which ports are open on your computer, you may run the command "netstat -npl" and get results like this:

Proto Local Address Foreign Address State


This result indicates that port 80 on your computer is open and listening for incoming connections (the asterisk means "any" address).

The source, or local address in this case, is, which means that it is open to all interfaces on the machine, regardless of their IP address.

You can use as the source address, allowing incoming connections on both networks.

In cases where you only want to see what ports are open on a specific interface or IP address, you can use the -l flag with the netstat command.

Linux course for Beginners

There are many reasons why it is valuable for you to learn Linux. If you are looking for new opportunities in IT, Linux skills are in high demand.

For example, if you are developing applications, it’s likely your application or its runtime is hosted on Linux. If you’re working in the cloud, your cloud instances may be based on Linux, and your private or public cloud environment is also probably based on Linux.

We highly recommend this course on Coursera to Linux beginners. Coursera offers a variety of Linux courses from top universities and organizations. Coursera also offers specializations in Linux and cloud computing.

This course will provide you with a basic introduction to Linux® skills using Red Hat® Enterprise Linux 8. It will show you how a Linux system is organized, and will demonstrate introductory system administration tasks, which you will be able to practice on your own.

What you will learn from this course

  • Getting Started with Red Hat Enterprise Linux
  • Accessing the Command Line
  • Managing Files From the Command Line
  • Creating, Viewing, and Editing Text Files
  • Managing Local Linux Users and Groups
  • Controlling Access to Files with Linux File System Permissions
  • Monitoring and Managing Linux Processes
  • Installing and Updating Software Packages
  • Comprehensive Review

After completing this course, you will have a solid introduction to working with Linux from the command line, using Red Hat Enterprise Linux 8 as a model. In applying these skills, you will be able to perform fundamental operational tasks, whether your Linux machine is on your desk or on a remote system across the Internet.

Top reviews

BS Jul 29, 2022

Awesome experience with my first course at Coursera. I really enjoyed the whole course and it was fun to play with the linux commands in AWS EC2. Thank you so much for such great content.

Completed this course and obtained my first certification in Linux. It was very fun and engaging. I would recommend anyone looking at getting into Linux

AV Jun 30, 2021

As someone new to the Linux environment, I have to say this course was excellent. The lessons and documentation were easy to read and understand, the labs were informative and easy to follow.

The presenter was well spoken and easy to understand. At no point in time did I feel overwhelmed or clueless. Definitely one of the best courses I’ve done on this site.

Learn more details about this course and see how it can help you level up your Linux skills


In conclusion, the IP address is often used as a "wildcard" address, meaning that it can be used to represent any IP address. For example, if a server is configured to listen on, it will accept connections from any IP address.

Understanding what means can be useful in diagnosing network issues and ensuring that your machine is properly secured!

Top comments (0)