UDP port check

What the UDP port check does

Sends a UDP datagram to the host and port and interprets the reply or the ICMP error to classify the port as open, filtered or closed.

• Use it for UDP services such as game servers, VoIP, VPN or custom protocols, where a TCP check tells you nothing.
• UDP has no handshake, so an open port that stays silent shows as filtered. Ports of well-known amplification services (DNS, NTP, SNMP…) are blocked. Free account required.