# outbound\_teredo **Explanation** The outbound\_teredo NDM is designed to detect Teredo packets leaving the customer network. Teredo is a protocol for encapsulating IPv6 packets in IPv4 UDP packets. Teredo can be used for legitimate communication between IPv6-enabled networks or devices over an IPv4 infrastructure. However, it can also be exploited by attackers to bypass security measures, and can allow bidirectional access behind a firewall over IPv6. **What to Look For** Teredo is often enabled by default on Windows machines and some communication with the Internet may be expected. If Teredo is not expected or authorized in the environment, investigate the sources and destinations of the traffic to determine if there are any signs of malicious activity. Many organizations chose to block outbound Teredo traffic at their firewalls. **Related MITRE ATT\&CK Categories** [Command and Control: Protocol Tunneling, Technique T1572 - Enterprise](https://attack.mitre.org/techniques/T1572) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.fusion.vectra.ai/detection-models/library/operational-governance/outbound_teredo.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.