shadowsocks/shadowsocks-windows · warning · ArgumentException

Port out of range

Error message

Port out of range

What it means

ArgumentException thrown by CheckPort when a port is <= 0 or > 65535. Valid TCP/UDP ports are 1..65535. This is part of the server-config validation flow (also reached via CheckLocalPort) used when loading or saving a Shadowsocks server entry.

Source

Thrown at shadowsocks-csharp/Model/Configuration.cs:355

                config.configs.Insert(index.GetValueOrDefault(config.configs.Count), server);

                //if (index.HasValue)
                //    config.configs.Insert(index.Value, server);
                //else
                //    config.configs.Add(server);
            }
            return server;
        }

        public static Server GetDefaultServer()
        {
            return new Server();
        }

        public static void CheckPort(int port)
        {
            if (port <= 0 || port > 65535)
                throw new ArgumentException(I18N.GetString("Port out of range"));
        }

        public static void CheckLocalPort(int port)
        {
            CheckPort(port);
            if (port == 8123)
                throw new ArgumentException(I18N.GetString("Port can't be 8123"));
        }

        private static void CheckPassword(string password)
        {
            if (string.IsNullOrEmpty(password))
                throw new ArgumentException(I18N.GetString("Password can not be blank"));
        }

        public static void CheckServer(string server)
        {
            if (string.IsNullOrEmpty(server))

View on GitHub (pinned to 891d971682)

Solutions

1. Set the port to a value in 1..65535, preferring the non-privileged range 1024..65535.
2. Re-open the config dialog and correct the entry, then save.
3. Manually fix the server_port field in gui-config.json and reload.

Example fix

// before
Configuration.CheckPort(70000); // throws

// after
int port = 70000;
if (port < 1 || port > 65535) port = 8388; // sane default
Configuration.CheckPort(port);

static bool IsValidPort(int p) => p > 0 && p <= 65535;
if (!IsValidPort(port)) {
    // reject in the UI before calling CheckPort
    return;
}

try { Configuration.CheckPort(port); }
catch (ArgumentException ex) { /* show ex.Message in the UI, keep the dialog open */ }

When it happens

Trigger: A user enters 0, a negative number, or a value above 65535 in the server config dialog. gui-config.json is hand-edited with an out-of-range server_port. An int parse of an oversized port string overflows the valid range.

Common situations: Typo such as 65536 or 808080. Port field left blank (parsed as 0). Copy-paste of a port that included extra digits.

Related errors

• Port can't be 8123
• Server IP can not be blank
• Unknown forward proxy.
• Password can not be blank
• Timeout is invalid, it should not exceed {0}

AI-assisted analysis of shadowsocks/shadowsocks-windows@891d971682 (2026-08-13). Data as JSON: /api/errors/39b2538713ac86d5. Report an issue: GitHub.