Advanced Options (Custom Payload)

If left empty, the system will automatically inject a standardized probe for known ports (DNS, NTP, SNMP, Source Engine, etc.).

資訊 Ping HTTP TCP UDP MTR DNS

A port is required for UDP checks.

檢查 UDP 連接埠開啟狀態：全球連線測試

Enter a domain or IP address with a port (e.g., 8.8.8.8:53) to begin the global UDP check.

Examples: 8.8.8.8:53 time.nist.gov:123 1.1.1.1:5060

Commonly Used UDP Ports

A list of the most frequent destination ports encountered in modern UDP network monitoring.

Port	Service	Description
53	DNS	Domain Name System; resolves hostnames to IP addresses.
67	DHCP	DHCP Server; used for dynamic IP allocation.
123	NTP	Network Time Protocol; synchronizes system clocks.
161	SNMP	Simple Network Management Protocol; used for network monitoring.
500	ISAKMP	ISAKMP; used for setting up IPsec VPN tunnels.
3478	STUN	STUN; used for NAT traversal in VoIP and WebRTC.
5060	SIP	Session Initiation Protocol (SIP); used for VoIP signaling.
27015	Source Engine	Source Engine Query; used by game servers (CS:GO, TF2, Rust).

Global UDP Port Checker & Payload Injector

我們的 UDP 連接埠檢查工具會從全球各地，向目標主機上的特定連接埠發送使用者資料封包協定 (UDP) 封包。因為 UDP 是一種無連線協定 (不同於 TCP，它不執行握手處理)，要驗證 UDP 連接埠是否真正「開啟」，必須等待目標的回應或是等待直到逾時 (timeout) 為止。像是 DNS (通訊埠 53)、NTP (通訊埠 123) 以及眾多的遊戲伺服器等服務，都非常依賴 UDP 傳輸。

Stateless Routing & Payload Injection

當我們的監控節點送出探測封包 (probe) 時，如果主機回傳 ICMP 的「Port Unreachable (連接埠無法連線)」訊息，我們就能確定該連接埠是關閉的。如果在逾時之前都沒有收到任何回應，該連接埠可能是開啟的，或者封包可能只是被防火牆給阻擋 (dropped) 了。我們的工具能夠在全球不同的地理位置，精確地分辨這些狀態之間的差異，為您提供服務 UDP 狀態的完整樣貌。

Firewall & DDoS Mitigation Testing

UDP is the primary vector for massive volumetric DDoS attacks (like NTP or DNS amplification). Consequently, modern cloud firewalls and ISP scrubbing centers often deploy aggressive UDP rate-limiting or outright protocol drops. Utilizing a globally distributed UDP test helps security engineers confirm that legitimate traffic is bypassing the firewall rules correctly without triggering false-positive DDoS mitigation filters.

Gaming, VoIP, and Streaming Analysis

Real-time applications such as multiplayer game servers (Source Engine, Unreal), VoIP communications (SIP/RTP), and live video streaming rely almost exclusively on UDP to minimize latency. Dropped UDP packets manifest as voice jitter or game lag. Our Live UDP Check allows you to continuously monitor a target over a 60-second window, plotting latency spikes and packet loss on a real-time chart to diagnose transient network instability.