🛠️️ CLI tool to easily bind localhost network interface with additional IP and ensure matching record in /etc/hosts.

v1.3 2023-08-11 13:57 UTC


🛠️️ CLI tool to easily bind localhost network interface with additional IP and ensure matching record in /etc/hosts.

This is a helper tool to be installed via composer global to machines where the localhost deployment process of Docker composition (via docker-compose.yaml) is prepared in a way that it binds the ports on IP from localhost subnet block and multiple of such compositions should be allowed to run in parallel (differentiated by the IP).

Practically speaking this tool ensures that the localhost network interface (lo0 on OS X) will also have another IP from localhost subnet block (for example and there will entry in /etc/hosts for particular domain routing to that IP (for example example.test).

Supported platforms:

Platform Support

Required underlying utilities:

  • sudo
  • ifconfig
  • sed



composer global require kiwicom/loopbind

Then if you have composer bin directory on the PATH you can use it by calling loopbind in the CLI. So you can initialize the configuration with a CLI wizard:

$ loopbind init
> ENV variable name to extract IP address from (leave empty if you want to provide manually or want random one):
> Do you want to generate random free local IP:
>  [0] yes
>  [1] no
> > no
> IPv4 address from local block:
> Hostname (leave empty to continue):
> hostname
> Hostname (leave empty to continue):
> New config file `.loopbind.json` was created.
> Do you want to create .env file with variable IP:
>  [0] yes
>  [1] no
> > yes
> File `.env` was created with variable `IP` set to ``.
> You appear to have .docker-compose.yml file in your directory. Run `docker compose stop`, replace port binding from `"80:80"` to `"$IP:80:80"` and then `docker copmose up`.


In the project root define a file named .loopbind.json with following content:

    "localIPAlias": "",
    "hostname": "foobar.test"

Or when you need to bind multiple hostnames:

    "localIPAlias": "",
    "hostname": ["www.foobar.test","foobar.test"]

Then in this directory you can run loopbind apply to run commands to ensure the binding. Also, you can run loopbind unapply to remove it and loopbind show to show the configuration and its status.

The commands are idempotent so repeated apply/unapply does nothing (and the apply command does not even need to run the command again).

Please note, that the config is expected to be in the current working directory.


This projects uses following coding standard:

  • PHPStan analysis (composer stan)
  • PHPUnit tests. (composer unit)

However, due to the expected side effects (changing the computer configuration after run) and application of KISS only a subset of functionality is tested automatically. Hence, testing of:

  • ApplyCommand
  • UnapplyCommand

should be done manually.