# What is UDP?

UDP sends datagrams without providing TCP’s built-in ordered stream and delivery guarantees.

Website: https://zenshield.com/glossary/udp

Canonical URL: https://zenshield.com/glossary/udp

Page reviewed: 2026-09-09

UDP sends datagrams without providing TCP’s built-in ordered stream and delivery guarantees. Applications can decide how to handle missing or late traffic themselves. That makes UDP useful for different designs, but the protocol name alone cannot tell you the quality of an application.

## A practical example

In a live voice call, a late fragment may be less useful than the next fragment arriving on time. In a file transfer, every part may still be required. The application’s design determines what happens after a datagram is delayed or lost.

## What to check

When troubleshooting, record the actual symptom: failure to start, intermittent audio or repeated disconnections. If the application documents alternate connection settings, compare them under the same conditions. Ask a managed-network administrator about permitted traffic rather than disabling protections to force one transport.

## What it does not tell you

UDP does not automatically mean faster, unencrypted or unreliable in the everyday sense. Higher-level protocols can add reliability and encryption. Zenshield’s supported transports are not established by this glossary definition; check current product documentation for any app-specific claim.

Read the [technical reference](https://developer.mozilla.org/en-US/docs/Glossary/UDP) for the underlying definition. For a connection that is failing now, use the [troubleshooting guide](https://zenshield.com/help/connection-problems). To choose an app, follow the [VPN selection worksheet](https://zenshield.com/learn/choosing-a-vpn).

## Sources
- https://developer.mozilla.org/en-US/docs/Glossary/UDP