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.

check-host.cc:80 のレポート

Name: Check-Host check-host.cc: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 check-host.cc:80

Apr 20, 2026 20:12:49 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	-	34.36.183.77
Australia, Sydney	Timeout	-	34.36.183.77
Bosnia and Herzegovina, Novi Travnik	Timeout	-	34.36.183.77
Bulgaria, Sofia	Timeout	-	34.36.183.77
Canada, Montreal	Timeout	-	34.36.183.77
Switzerland, Bern	Timeout	-	34.36.183.77
Chile, Santiago	Timeout	-	34.36.183.77
China, Hohhot	Timeout	-	34.36.183.77
Germany, Nuernberg	Timeout	-	34.36.183.77
Germany, Frankfurt am Main	Timeout	-	34.36.183.77
Germany, Frankfurt am Main	Timeout	-	34.36.183.77
Germany, Limburg	Timeout	-	34.36.183.77
Germany, Frankfurt am Main	Timeout	-	34.36.183.77
Germany, Duesseldorf	Timeout	-	34.36.183.77
Denmark, Glostrup Municipality	Timeout	-	34.36.183.77
Spain, Bilbao	Timeout	-	34.36.183.77
Finland, Helsinki	Timeout	-	34.36.183.77
Finland, Helsinki	Timeout	-	34.36.183.77
France, Gravelines	Timeout	-	34.36.183.77
France, Paris	Timeout	-	34.36.183.77
United Kingdom, London	Timeout	-	34.36.183.77
Georgia, Tbilisi	UDP checks unavailable: SOCKS5 proxy does not support UDP ASSOCIATE	-	check-host.cc
Greece, Athens	UDP checks unavailable: SOCKS5 proxy does not support UDP ASSOCIATE	-	check-host.cc
Hong Kong, Hong Kong	Timeout	-	34.36.183.77
Croatia, Zagreb	Timeout	-	34.36.183.77
Hungary, Budapest	Timeout	-	34.36.183.77
Indonesia, Jakarta	Timeout	-	34.36.183.77
Israel, Petach Tikwa	Timeout	-	34.36.183.77
Israel, Netanja	Timeout	-	34.36.183.77
India, New Delhi	Timeout	-	34.36.183.77
Iceland, Reykjavik (Miðborg)	Timeout	-	34.36.183.77
Kuwait, Kuwait City	UDP checks unavailable: SOCKS5 proxy does not support UDP ASSOCIATE	-	check-host.cc
Lithuania, Pilaite	Timeout	-	34.36.183.77
Latvia, Riga	Timeout	-	34.36.183.77
Moldova, Chisinau	Timeout	-	34.36.183.77
Netherlands, Amsterdam	Timeout	-	34.36.183.77
Netherlands, Amsterdam	Timeout	-	34.36.183.77
Netherlands, Amsterdam	Timeout	-	34.36.183.77
Netherlands, Amsterdam	Timeout	-	34.36.183.77
Norway, Oslo	Timeout	-	34.36.183.77
Poland, Warsaw	Timeout	-	34.36.183.77
Romania, Bacău	Timeout	-	34.36.183.77
Romania, Bucharest	Timeout	-	34.36.183.77
Serbia, Belgrade	Timeout	-	34.36.183.77
Russia, St Petersburg	Timeout	-	34.36.183.77
Singapore, Singapore	Timeout	-	34.36.183.77
Turkey, Istanbul	Timeout	-	34.36.183.77
Taiwan, Taipei	Timeout	-	34.36.183.77
United States, Miami	Timeout	-	34.36.183.77
United States, Dallas	Timeout	-	34.36.183.77
United States, Kansas City	Timeout	-	34.36.183.77
United States, Dallas	Timeout	-	34.36.183.77
South Africa, Johannesburg	Timeout	-	34.36.183.77