shadowsocks/shadowsocks-rust · error

failed to create ServerConfig, error: {}

Error message

failed to create ServerConfig, error: {}

What it means

After parsing the CLI server address, password and method, create() calls shadowsocks-service's ServerConfig::new to validate them; any error it returns (e.g. invalid server address format, method/password combination rejected) is surfaced via this panic. It is a wrapper: the underlying cause is in the `{}` payload.

Source

Thrown at src/service/server.rs:361

                    if method.is_none() {
                        // If method doesn't need a key (none, plain), then we can leave it empty
                        String::new()
                    } else {
                        match crate::password::read_server_password(svr_addr) {
                            Ok(pwd) => pwd,
                            Err(..) => panic!("`password` is required for server {svr_addr}"),
                        }
                    }
                }
            };

            let svr_addr = svr_addr.parse::<ServerAddr>().expect("server-addr");
            let timeout = matches.get_one::<u64>("TIMEOUT").map(|x| Duration::from_secs(*x));

            let mut sc = match ServerConfig::new(svr_addr, password, method) {
                Ok(sc) => sc,
                Err(err) => {
                    panic!("failed to create ServerConfig, error: {}", err);
                }
            };
            if let Some(timeout) = timeout {
                sc.set_timeout(timeout);
            }

            if let Some(p) = matches.get_one::<String>("PLUGIN").cloned() {
                let plugin = PluginConfig {
                    plugin: p,
                    plugin_opts: matches.get_one::<String>("PLUGIN_OPT").cloned(),
                    plugin_args: Vec::new(),
                    plugin_mode: matches
                        .get_one::<String>("PLUGIN_MODE")
                        .map(|x| {
                            x.parse::<Mode>()
                                .expect("plugin-mode must be one of `tcp_only` (default), `udp_only` and `tcp_and_udp`")
                        })
                        .unwrap_or(Mode::TcpOnly),

View on GitHub (pinned to 8eb0f0a65b)

Solutions

1. Read the inner error text after `error:` — it names the exact validation that failed
2. Use a well-formed server address: host:port, or [ipv6]:port e.g. `-s '[::1]:8388'`
3. Verify the `--method` and `--password` pair is valid for that cipher (correct key length / encodable password)
4. Prefer a JSON config file (`-c config.json`) so validation errors come back as structured LoadConfigFailure instead of CLI panics

Example fix

// before
ssserver -s '8388' -m aes-256-gcm -p secret
// after
ssserver -s '0.0.0.0:8388' -m aes-256-gcm -p secret

fn looks_like_host_port(s: &str) -> bool {
    if s.starts_with('[') { s.contains("]:") } else { s.rsplit_once(':').map(|(h,p)| !h.is_empty() && p.parse::<u16>().is_ok()).unwrap_or(false) }
}
if !looks_like_host_port(server_addr) { eprintln!("bad -s value: {server_addr}"); std::process::exit(2); }

// panic is not catchable in stable Rust; inspect the spawned process stderr:
let out = Command::new("ssserver").args(&args).output()?;
if !out.status.success() { eprintln!("ssserver failed: {}", String::from_utf8_lossy(&out.stderr)); }

When it happens

Trigger: `--server-addr` fails ServerAddr parsing beyond the earlier expect (bad host/port forms handled by ServerConfig), or ServerConfig::new rejects the (addr, password, method) combination, e.g. a method requiring a key with invalid key material.

Common situations: Malformed `-s` values like `8388` (missing host), IPv6 literals without brackets, or password bytes that fail key derivation constraints for the chosen cipher.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

• `password` is required for server {svr_addr}
• failed to create ServerConfig, error: {}
• not supported `protocol` "{p}"
• `local-addr` is required for protocol {}
• `password` is required for server {svr_addr}

AI-assisted analysis of shadowsocks/shadowsocks-rust@8eb0f0a65b (2026-09-09). Data as JSON: /api/errors/2e90afae689ed682. Report an issue: GitHub.