Dualstack IPv6/IPv4 support

docs/settings.md

@@ -22,7 +22,7 @@ For example, in case you want to run the app on port `5000`, just set the enviro
 
 ## Socket Binding
 
-* `--host <str>` - Bind socket to this host. Use `--host 0.0.0.0` to make the application available on your local network. IPv6 addresses are supported, for example: `--host '::'`. **Default:** *'127.0.0.1'*.
+* `--host <str>` - Bind socket to this host. May be used multiple times. If unused, then by default all interfaces are assumed and a list of multiple sockets will be used. Use `--host 127.0.0.1` to make the application available only on your local machine. IPv6 addresses are supported, for example: `--host '::'`. **Default:** *'auto'*.
 * `--port <int>` - Bind to a socket with this port. **Default:** *8000*.
 * `--uds <path>` - Bind to a UNIX domain socket, for example `--uds /tmp/uvicorn.sock`. Useful if you want to run Uvicorn behind a reverse proxy.
 * `--fd <int>` - Bind to socket from this file descriptor. Useful if you want to run Uvicorn within a process manager.

uvicorn/config.py

@@ -175,7 +175,7 @@ class Config:
     def __init__(
         self,
         app: ASGIApplication | Callable[..., Any] | str,
-        host: str = "127.0.0.1",
+        host: list[str] | str | None = None,
         port: int = 8000,
         uds: str | None = None,
         fd: int | None = None,

uvicorn/main.py

@@ -61,10 +61,8 @@ def print_version(ctx: click.Context, param: click.Parameter, value: bool) -> No
 @click.argument("app", envvar="UVICORN_APP")
 @click.option(
     "--host",
-    type=str,
-    default="127.0.0.1",
+    multiple=True,
     help="Bind socket to this host.",
-    show_default=True,
 )
 @click.option(
     "--port",
@@ -460,7 +458,7 @@ def main(
 def run(
     app: ASGIApplication | Callable[..., Any] | str,
     *,
-    host: str = "127.0.0.1",
+    host: list[str] | str | None = None,
     port: int = 8000,
     uds: str | None = None,
     fd: int | None = None,

uvicorn/middleware/proxy_headers.py

@@ -19,7 +19,7 @@ class ProxyHeadersMiddleware:
     def __init__(
         self,
         app: ASGI3Application,
-        trusted_hosts: list[str] | str = "127.0.0.1",
+        trusted_hosts: list[str] | str | None = None,
     ) -> None:
         self.app = app
         if isinstance(trusted_hosts, str):

uvicorn/server.py

@@ -194,7 +194,7 @@ def _log_started_message(self, listeners: Sequence[socket.SocketType]) -> None:
 
         else:
             addr_format = "%s://%s:%d"
-            host = "0.0.0.0" if config.host is None else config.host
+            host = config.host
             if ":" in host:
                 # It's an IPv6 address.
                 addr_format = "%s://[%s]:%d"