How do I check if a UDP port is open online?

Enter a host and UDP port (e.g. 8.8.8.8:53) in the UDP checker. The tool sends protocol-appropriate payloads from 50+ global nodes — for example, a real DNS query to port 53 or an NTP request to port 123 — and reports whether a valid response was received from each location.

Why does UDP port testing require a payload?

Unlike TCP, UDP has no handshake. An empty packet sent to most UDP services produces no response because the application is waiting for meaningful data before replying. The tool automatically injects the correct payload for known ports (DNS/53, NTP/123, SNMP/161, game servers/27015) to get a real, meaningful response.

How do I test if my VPN UDP port is reachable?

Enter your VPN server IP and port (typically UDP 1194 for OpenVPN or UDP 51820 for WireGuard) and run the UDP check. Results from multiple global nodes will show whether your VPN port is accessible worldwide or blocked by specific ISPs or regional networks.

Can I test game server ports with this UDP checker?

Yes. For Source Engine game servers (CS:GO, TF2, Rust) on port 27015, the tool automatically sends a valid Source Engine query packet. For other game servers, you can enter a custom hex payload in the advanced options. Results show which global regions can reach your game server.

cn-hoh-alibaba.check-host.eu:80 のレポート

Name: Check-Host cn-hoh-alibaba.check-host.eu:80 UDP ポート到達性チェック
Author: Check-Host

Info Ping HTTP TCP UDP MTR DNS

report.report_types.udp cn-hoh-alibaba.check-host.eu:80

Apr 21, 2026 07:55:03 UTC に確認 |

| 再チェック |

拠点	結果	応答時間	IP アドレス
Albania, Tirana	Timeout	-	39.104.200.240
Australia, Sydney	Timeout	-	39.104.200.240
Bosnia and Herzegovina, Novi Travnik	Timeout	-	39.104.200.240
Bulgaria, Sofia	Timeout	-	39.104.200.240
Canada, Montreal	Timeout	-	39.104.200.240
Switzerland, Bern	Timeout	-	39.104.200.240
Chile, Santiago	Timeout	-	39.104.200.240
China, Hohhot	Timeout	-	39.104.200.240
Germany, Nuernberg	Timeout	-	39.104.200.240
Germany, Frankfurt am Main	Timeout	-	39.104.200.240
Germany, Frankfurt am Main	Timeout	-	39.104.200.240
Germany, Limburg	Timeout	-	39.104.200.240
Germany, Frankfurt am Main	Timeout	-	39.104.200.240
Germany, Duesseldorf	Timeout	-	39.104.200.240
Denmark, Glostrup Municipality	Timeout	-	39.104.200.240
Spain, Bilbao	Timeout	-	39.104.200.240
Finland, Helsinki	Timeout	-	39.104.200.240
Finland, Helsinki	Timeout	-	39.104.200.240
France, Gravelines	Timeout	-	39.104.200.240
France, Paris	Timeout	-	39.104.200.240
United Kingdom, London	Timeout	-	39.104.200.240
Georgia, Tbilisi	UDP checks unavailable: SOCKS5 proxy does not support UDP ASSOCIATE	-	cn-hoh-alibaba.check-host.eu
Greece, Athens	UDP checks unavailable: SOCKS5 proxy does not support UDP ASSOCIATE	-	cn-hoh-alibaba.check-host.eu
Hong Kong, Hong Kong	Timeout	-	39.104.200.240
Croatia, Zagreb	Timeout	-	39.104.200.240
Hungary, Budapest	Timeout	-	39.104.200.240
Indonesia, Jakarta	Timeout	-	39.104.200.240
Israel, Petach Tikwa	Timeout	-	39.104.200.240
Israel, Netanja	Timeout	-	39.104.200.240
India, New Delhi	Timeout	-	39.104.200.240
Iceland, Reykjavik (Miðborg)	Timeout	-	39.104.200.240
Italy, Como	Timeout	-	39.104.200.240
Kuwait, Kuwait City	UDP checks unavailable: SOCKS5 proxy does not support UDP ASSOCIATE	-	cn-hoh-alibaba.check-host.eu
Lithuania, Pilaite	Timeout	-	39.104.200.240
Latvia, Riga	Timeout	-	39.104.200.240
Moldova, Chisinau	Timeout	-	39.104.200.240
Netherlands, Amsterdam	Timeout	-	39.104.200.240
Netherlands, Amsterdam	Timeout	-	39.104.200.240
Netherlands, Amsterdam	Timeout	-	39.104.200.240
Netherlands, Amsterdam	Timeout	-	39.104.200.240
Norway, Oslo	Timeout	-	39.104.200.240
Poland, Warsaw	Timeout	-	39.104.200.240
Romania, Bacău	Timeout	-	39.104.200.240
Romania, Bucharest	Timeout	-	39.104.200.240
Serbia, Belgrade	Timeout	-	39.104.200.240
Russia, St Petersburg	Timeout	-	39.104.200.240
Singapore, Singapore	Timeout	-	39.104.200.240
Turkey, Istanbul	Timeout	-	39.104.200.240
Taiwan, Taipei	Timeout	-	39.104.200.240
United States, Miami	Timeout	-	39.104.200.240
United States, Dallas	Timeout	-	39.104.200.240
United States, Kansas City	Timeout	-	39.104.200.240
United States, Dallas	Timeout	-	39.104.200.240
South Africa, Johannesburg	Timeout	-	39.104.200.240