# nmap -p 30115 -sU -P0 192.168.0.23

Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2012-01-06 12:14 EET
Interesting ports on kkappsrv1.kentkart.com.tr (192.168.0.23):
PORT STATE SERVICE
30115/udp open|filtered unknown

tcp/ip e aşina olan arkadaşlar 3-way handshake yapılmadığı halde nasıl oluyor da udp port açık mı kapalı mı kontrolü yapılabiliyor diye merak edebilirler…

Alıntı:

When a generic UDP packet is sent to a UDP port of a remote host, one of the following occurs:

• If the UDP port is open, the packet is accepted, no response packet is sent.
• If the UDP port is closed, an ICMP packet is sent in response with the appropriate error code such as Destination Unreachable.

Kaynak: https://community.qualys.com/docs/DOC-1185