What Does The IP Address 0.0.0.0 Really Mean? What Are Its Different Uses?

Short Bytes: The IP address 0.0.0.0 signifies different uses at different places. Usually, it’s a non-routable meta address that’s not bound to any particular remote address. Dealing with servers, it means all IPv4 addresses in the local machine. In route entry’s context, it usually means the default route. In IPv6, IP address 0.0.0.0 is represented by ::0 or just ::.

You might have heard about the IP address 0.0.0.0 but never thought much about it. Some of you would be knowing that it’s a ‘no particular address’ placeholder’. But, what else? What does it really mean in different situations? Well, here I’ll try to answer these frequently asked questions just the way I answered your queries on 127.0.0.1.

What is the meaning of IP address 0.0.0.0?

Sometimes 0.0.0.0 is also called wildcard address or unspecified address. Officially, it’s called “source address for this host on this network” (RFC 5735, Section 3).

If you perform a Google search, you’ll come across different explanations that’ll tell 0.0.0.0 address specifies you don’t have an IP address or it’s the default route. Read some more confusing articles and they’ll tell you that it’s an IP address you get from DHCP.

Let me tell you that all these answers are right in different scenarios. Additionally, 0.0.0.0 also specifies all IP addresses on all interfaces on the systems. It’s a non-routable meta-address that’s used to define an unknown or invalid target. If we talk about servers, 0.0.0.0 means all IPv4 addresses on the local machine. In the case of a route entry, it means the default route.

The client devices like PCs show 0.0.0.0 address when they aren’t connected to any TCP/IP network. A device may get this address by default if it’s offline. In the case of address assignment failures, it may be automatically assigned by DHCP. Just in case your device is set to this address, it can’t talk to any other devices on the network over IP.

In some cases, it can also be set as a device’s subnet mask. Unlike an IP address, a subnet mask has no particular practical use.

Just like any other IP address, 0.0.0.0 is a valid syntax. In some situations, using just 0 will work with the same effect. In IPv6, IP address 0.0.0.0 is represented by ::0 or just ::.

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Also Read: Why Is Localhost’s IP Address 127.0.0.1? What Is Its Meaning?