"subnet": "10.1.0.0/16",
        "type": "host-local"
      },
      "type": "bridge"
    },
    {
      "sysctl": {
        "net.core.somaxconn": "500"
      },
      "type": "tuning"
    },
    {
      "kubernetes": {
        "cni_bin_dir": "/path/cni/bin",
        "kubeconfig": "/path/to/kubeconfig"
      },
      "name": "istio-cni",
      "plugin_log_level": "debug",

```console
$ uvicorn main:app --host 0.0.0.0 --port 80

<span style="color: green;">INFO</span>:     Uvicorn running on http://0.0.0.0:80 (Press CTRL+C to quit)
```

</div>

////

//// tab | Hypercorn

<div class="termy">

```console
$ hypercorn main:app --bind 0.0.0.0:80

Running on 0.0.0.0:8080 over http (CTRL + C to quit)
```

</div>

////

/// warning | "Предупреждение"

👆 💪 📨 & 📨 💱, ✍, & 🎻 💽.

## 🔄 ⚫️

🚥 👆 📁 📛 `main.py`, 🏃 👆 🈸 ⏮️:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

📂 👆 🖥 <a href="http://127.0.0.1:8000" class="external-link" target="_blank">http://127.0.0.1:8000</a>.

👆 🔜 👀 🙅 📃 💖:

```Python
{!../../docs_src/first_steps/tutorial001.py!}
```

📁 👈 📁 `main.py`.

🏃 🖖 💽:

<div class="termy">

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]
<span style="color: green;">INFO</span>:     Started server process [28722]

        "subnet": "10.1.0.0/16",
        "type": "host-local"
      },
      "type": "bridge"
    },
    {
      "sysctl": {
        "net.core.somaxconn": "500"
      },
      "type": "tuning"
    },
    {
      "ambient_enabled": false,
      "cni_agent_run_dir": "/path/to/kubeconfig",
      "dns": {},
      "exclude_namespaces": [
        ""
      ],
      "ipam": {},

        "subnet": "10.1.0.0/16",
        "type": "host-local"
      },
      "type": "bridge"
    },
    {
      "sysctl": {
        "net.core.somaxconn": "500"
      },
      "type": "tuning"
    }
  ]

  // The total number of nodes that should be running the daemon
  // pod (including nodes correctly running the daemon pod).
  // More info: https://kubernetes.io/docs/concepts/workloads/controllers/daemonset/
  optional int32 desiredNumberScheduled = 3;

  // The number of nodes that should be running the daemon pod and have one
  // or more of the daemon pod running and ready.
  optional int32 numberReady = 4;

         "type": "row"
      },
      {
         "datasource": {
            "type": "datasource",
            "uid": "-- Mixed --"
         },
         "description": "Version number of each running instance",
         "fieldConfig": {
            "defaults": {
               "custom": {
                  "fillOpacity": 10,
                  "gradientMode": "hue",
                  "showPoints": "never"

      "ipam": {
        "type": "host-local",
        "subnet": "10.1.0.0/16",
        "gateway": "10.1.0.1"
      },
      "dns": {
        "nameservers": [ "10.1.0.1" ]
      }
    },
    {
      "type": "tuning",
      "sysctl": {
        "net.core.somaxconn": "500"
      }
    }
  ]

Even if they are all in `localhost`, they use different protocols or ports, so, they are different "origins".

## Steps

So, let's say you have a frontend running in your browser at `http://localhost:8080`, and its JavaScript is trying to communicate with a backend running at `http://localhost` (because we don't specify a port, the browser will assume the default port `80`).