I have an odoo instance inside docker. Long story short, I was checking visitors of my instance and I saw this:

http://0/

What is this?

The final boss of the internet

Truncated IP. I don't remember the rules though. It's probably equivalent to 0.0.0.0 which is localhost.

@gronostaj correct, it's an alias to 0.0.0.0, which implies localhost in most cases

@vintprox not really.

Yes it is situation dependent, but 0.0.0.0 has nothing to do with localhost.

It usually means "non routeable".

It's widely used to match all known addresses to a port (eg 0.0.0.0:80) or as an address for a default gateway.

There are things like Zero / mDNS / Bonjour / AVAHI / DHCP Discover / APIPA and I guess a few more who may utilize this.

localhost is DNS. And tricky, because localhost can be anything. Usually 127.0.0.1 on an loopback device, but it mustn't be that way.

@IntrusionCM I see! Thanks for the insight

@IntrusionCM @vintprox
In applications, 0.0.0.0 is listen on all bound ips.

In routing, it's the gateway

In DHCP it's, "I need an adult, and an IP kthxbai"

According to Wikipedia it could be a truncated IP address, as @gronostaj said. The rule is simple: stretch the last value over the remaining bytes. So 0 is 0.0.0.0.

The same page also lists 0.0.0.0/8 as a a special address block indicating the current network. However, according to RFC1122 it's only valid as the source address of an IP packet and only during initialization (Section 3.2.1.3).

That RFC also says that some hosts use 0.0.0.0 as a broadcast address, and therefore it should be accepted as such (Section 3.3.6).

But 0 could also be a hostname (RFC1123, Section 2.1).

Thanks everyone, though what I cannot understand, I have lots of http only connections tracked and they are all for one second duration. Even though I have nginx force redirection https and drop all connections made to IP instead of domain