diff --git a/README.md b/README.md
index bd5ab52..4b93fcc 100644
--- a/README.md
+++ b/README.md
@@ -68,11 +68,12 @@ Tunnel interface to proxy.
 Usage: tun2proxy [OPTIONS] --proxy <URL>
 
 Options:
-  -t, --tun <name>    Name of the tun interface [default: tun0]
-  -p, --proxy <URL>   Proxy URL in the form proto://[username[:password]@]host:port
-  -d, --dns <method>  DNS handling [default: virtual] [possible values: virtual, none]
-  -h, --help          Print help
-  -V, --version       Print version
+  -t, --tun <name>      Name of the tun interface [default: tun0]
+  -p, --proxy <URL>     Proxy URL in the form proto://[username[:password]@]host:port
+  -d, --dns <method>    DNS handling [default: virtual] [possible values: virtual, none]
+  -s, --setup <method>  Routing and system setup [possible values: auto]
+  -h, --help            Print help
+  -V, --version         Print version
 ```
 Currently, tun2proxy supports HTTP, SOCKS4/SOCKS4a and SOCKS5. A proxy is supplied to the `--proxy` argument in the
 URL format. For example, an HTTP proxy at `1.2.3.4:3128` with a username of `john.doe` and a password of `secret` is
diff --git a/src/main.rs b/src/main.rs
index 38cbe22..dfe3245 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -28,9 +28,9 @@ struct Args {
     )]
     dns: ArgDns,
 
-    /// Setup
+    /// Routing and system setup
     #[arg(short, long, value_name = "method", value_enum)]
-    setup: ArgSetup,
+    setup: Option<ArgSetup>,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, clap::ValueEnum)]
@@ -59,7 +59,7 @@ fn main() -> ExitCode {
     }
 
     let mut setup: Setup;
-    if args.setup == ArgSetup::Auto {
+    if args.setup == Some(ArgSetup::Auto) {
         setup = Setup::new(&args.tun, &args.proxy.addr.ip(), get_default_cidrs());
         if let Err(e) = setup.setup() {
             log::error!("{e}");