shadowsocks/shadowsocks-rust · error

`server_port` shouldn't be 0

Error message

`server_port` shouldn't be 0

What it means

When a server address is given as a socket address, its port must be non-zero. Port 0 is not a valid shadowsocks server port, so Config::check rejects it with ErrorKind::Malformed while iterating over all configured servers.

Source

Thrown at crates/shadowsocks-service/src/config.rs:2924

            return Err(err);
        }

        for inst in &self.server {
            let server = &inst.config;

            // Plugin shouldn't be an empty string
            if let Some(plugin) = server.plugin()
                && plugin.plugin.trim().is_empty()
            {
                let err = Error::new(ErrorKind::Malformed, "`plugin` shouldn't be an empty string", None);
                return Err(err);
            }

            // Server's domain name shouldn't be an empty string
            match server.addr() {
                ServerAddr::SocketAddr(sa) => {
                    if sa.port() == 0 {
                        let err = Error::new(ErrorKind::Malformed, "`server_port` shouldn't be 0", None);
                        return Err(err);
                    }

                    if self.config_type.is_local() {
                        // Only server could bind to INADDR_ANY
                        let ip = sa.ip();
                        if ip.is_unspecified() {
                            let err = Error::new(
                                ErrorKind::Malformed,
                                "`server` shouldn't be an unspecified address (INADDR_ANY)",
                                None,
                            );
                            return Err(err);
                        }
                    }

                    #[cfg(feature = "local-online-config")]
                    if self.config_type.is_online_config() {

View on GitHub (pinned to 8eb0f0a65b)

Solutions

1. Set server_port to a valid port (1-65535), typically 8388 or your provider's assigned port.
2. Fix the ss:// URL or SIP008 payload so the port is specified.
3. Add a pre-flight check in your tooling that asserts port > 0 before writing the config.

Example fix

// before
{ "server": "1.2.3.4", "server_port": 0, "password": "pw", "method": "aes-256-gcm" }

// after
{ "server": "1.2.3.4", "server_port": 8388, "password": "pw", "method": "aes-256-gcm" }

// Rust
let port: u16 = server_port;
assert!((1..=65535).contains(&port), "server_port must be 1-65535");

fn valid_port(p: u16) -> bool { p != 0 }

When it happens

Trigger: A server entry whose address is an IP:port socket address with port 0 — e.g. server_port = 0 in JSON/TOML, an ss:// URL like ss://...@host:0, or a SIP008 entry with port 0.

Common situations: Placeholder configs not yet filled in (server_port left at 0); subscription/registration data with a missing port defaulting to 0; template configs where the port variable was empty.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• `local_port` cannot be 0
• `local_udp_port` cannot be 0
• `server` shouldn't be an empty string, `server_port` shouldn
• missing `local_port`
• `protocol` invalid

AI-assisted analysis of shadowsocks/shadowsocks-rust@8eb0f0a65b (2026-09-09). Data as JSON: /api/errors/211722b1217fd8eb. Report an issue: GitHub.