louislam/uptime-kuma · error · Error

Packet size must be between ${PING_PACKET_SIZE_MIN} and ${PI

Error message

Packet size must be between ${PING_PACKET_SIZE_MIN} and ${PING_PACKET_SIZE_MAX} (default: ${PING_PACKET_SIZE_DEFAULT})

What it means

Thrown by Monitor.validate() for type "ping" when packetSize is set and falls outside [PING_PACKET_SIZE_MIN=1, PING_PACKET_SIZE_MAX=65500] bytes. The range reflects the ICMP payload size accepted by the underlying ping binary; values outside it are rejected by the OS before any packet is sent.

Source

Thrown at server/model/monitor.js:1712

            this.system_service_name = (this.system_service_name || "").trim();

            if (!this.system_service_name) {
                throw new Error(this.type === "pm2" ? "PM2 process name is required." : "Service Name is required.");
            }
        }

        if (this.type === "system-service" && !/^[a-zA-Z0-9._\-@]+$/.test(this.system_service_name)) {
            throw new Error("Invalid service name. Please use the internal Service Name (no spaces).");
        }

        if (this.type === "pm2" && /[\u0000-\u001F\u007F]/.test(this.system_service_name)) {
            throw new Error("Invalid PM2 process name.");
        }

        if (this.type === "ping") {
            // ping parameters validation
            if (this.packetSize && (this.packetSize < PING_PACKET_SIZE_MIN || this.packetSize > PING_PACKET_SIZE_MAX)) {
                throw new Error(
                    `Packet size must be between ${PING_PACKET_SIZE_MIN} and ${PING_PACKET_SIZE_MAX} (default: ${PING_PACKET_SIZE_DEFAULT})`
                );
            }

            if (
                this.ping_per_request_timeout &&
                (this.ping_per_request_timeout < PING_PER_REQUEST_TIMEOUT_MIN ||
                    this.ping_per_request_timeout > PING_PER_REQUEST_TIMEOUT_MAX)
            ) {
                throw new Error(
                    `Per-ping timeout must be between ${PING_PER_REQUEST_TIMEOUT_MIN} and ${PING_PER_REQUEST_TIMEOUT_MAX} seconds (default: ${PING_PER_REQUEST_TIMEOUT_DEFAULT})`
                );
            }

            if (this.ping_count && (this.ping_count < PING_COUNT_MIN || this.ping_count > PING_COUNT_MAX)) {
                throw new Error(
                    `Echo requests count must be between ${PING_COUNT_MIN} and ${PING_COUNT_MAX} (default: ${PING_COUNT_DEFAULT})`
                );

View on GitHub (pinned to 6b5ea01557)

Solutions

Set packetSize to a value between 1 and 65500, or omit it to use PING_PACKET_SIZE_DEFAULT.
If the value is entered in KB, multiply by 1024 and confirm it stays under 65500.
Cast the field to a Number before save to avoid a truthy string like "70000" bypassing numeric intent.

Example fix

// before
{ type: "ping", packetSize: 100000 }
// after
{ type: "ping", packetSize: 65500 }

Defensive patterns

Strategy: validation

Validate before calling

const [MIN, MAX] = [1, 65500];
function validPacketSize(v) {
  const n = Number(v);
  return !v || (Number.isInteger(n) && n >= MIN && n <= MAX);
}

Type guard

function isPacketSize(n) {
  return n == null || (typeof n === "number" && Number.isInteger(n) && n >= 1 && n <= 65500);
}

Try / catch

try {
  await bean.validate();
} catch (e) {
  if (/Packet size/.test(e.message)) return badRequest("packetSize must be 1..65500");
  throw e;
}

Prevention

Label the field as bytes, not KB.
Clamp rather than reject in the UI: Math.min(65500, Math.max(1, n)).

When it happens

Trigger: Save a ping monitor with packetSize=0 (falsy, skipped, so 0 is actually allowed-but-meaningless) or packetSize=-1, packetSize=70000, packetSize="abc" coerced to NaN. The check fires whenever packetSize is truthy and outside the bounds.

Common situations: User enters packet size in KB or bits instead of bytes (e.g. 1024 expecting 1KB but wanting 65536). Copying a config from a tool that uses a different max (e.g. 8192). Negative numbers from a misconfigured slider.

Related errors

AI-assisted analysis of louislam/uptime-kuma@6b5ea01557 (2026-08-12). Data as JSON: /api/errors/f13e2244d0009bc5. Report an issue: GitHub.