Liczba mnoga: UDPs

Acronym for User Datagram Protocol. The connectionless protocol within TCP/IP that corresponds to the transport layer in the ISO/OSI reference model. UDP converts data messages generated by an application into packets to be sent via IP, but it is “unreliable” because it does not establish a path between sender and receiver before transmitting and does not verify that messages have been delivered correctly. UDP is more efficient than TCP, so it is used for various purposes, including SNMP; the reliability depends on the application that generates the message. See also communications protocol, ISO/OSI reference model, packet, SNMP, TCP/IP. Compare IP, TCP.
(User Datagram Protocol).
One of the protocols for data transfer that is part of the TCP/IP suite of protocols. UDP is a protocol in that UDP makes no provision for acknowledgement of packets received.

Liczba mnoga: UDP scannings

Enumerating services on a target by using User Data- gram Protocol (UDP) packets.
UDP scanning is a stealthy but somewhat unreliable way of scanning a remote host to see which services are running on it. Some examples of common network services that use UDP include the following:
. Domain Name System (DNS)
. Dynamic Host Configuration Protocol (DHCP)
. Network Time Protocol (NTP)
..Remote Authentication Dial-In User Service (RADIUS)
. Routing Information Protocol (RIP)

Liczba mnoga: UDP tunnelings

A method of using User Datagram Protocol (UDP) to establish a covert channel.
Covert channels are communications channels that hide illicit information flow within a normal communications stream. One method of establishing a covert channel on an Internet Protocol (IP) network is to hide data in packets that normally don’t carry payloads. An example is UDP tunneling, which hides data in UDP packets used by such services as the Domain Name System (DNS) service. If firewalls are configured to pass such traffic, information can be leaked from the system without being detected by a firewall or intrusion detection system (IDS).
A common use of covert channels is communication with backdoors. Once an attacker has compromised a system and installed a backdoor, a covert channel allows the attacker to control the system or leak information from it using innocuous-looking UDP packets. One tool that attackers can use for this purpose is Loki, a program first published in Phrack magazine. The best way of preventing UDP tunneling is to block unnecessary UDP traffic at the firewall and disable on your host unnecessary services that use UDP.