Port 3544Teredo
Teredo is a network protocol designed to provide IPv6 connectivity to nodes that are located behind IPv4 NAT (Network Address Translation) devices. Implemented as a tunneling protocol, Teredo encapsulates IPv6 packets within IPv4 UDP datagrams, enabling seamless communication across IPv4 networks without requiring native IPv6 infrastructure. This ensures broader IPv6 adoption and maintains compatibility where direct IPv6 support is not feasible..
- transport
- udp
- in transit
- cleartext
- assignment
- official
- risk
- 4/10
- lookups
- 7,808
single transport
payload readable on path
registered with iana
caution
rank 655 of 993 · top 66%
Technical Details
what runs on :3544Teredo is an IPv6 transition technology specified in RFC 4380. It operates by tunneling IPv6 packets inside IPv4 UDP packets, which allows devices behind NATs to gain IPv6 connectivity. This tunneling alleviates the reliance solely on dual-stack deployments or native IPv6 connectivity.
The Teredo client obtains an IPv6 address through communication with a Teredo server on the public internet. This IPv6 address encodes the public IPv4 address and UDP port of the NAT device, facilitating bidirectional communication. Communication between peers is either direct or relayed via Teredo relays, depending on NAT traversal capabilities, which enables end-to-end IPv6 data exchange.
The protocol primarily uses UDP port 3544 and is enabled on many Windows operating systems by default. It plays a critical role during IPv6 adoption phases, but its relevance diminishes as native IPv6 connectivity becomes widespread.
Security Information
exposure of :3544risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
security averages 3.8 across 216 ports — this one sits 0.2 above.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
official
registered with iana for this service — scanners fingerprint it by number
reachable over
udp
udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite
security overview
Common Vulnerabilities:
- Attackers can abuse Teredo to bypass firewalls and security controls since it encapsulates IPv6 traffic within IPv4 UDP packets, potentially avoiding inspection.
- It can be leveraged by malware to establish covert communication channels across security boundaries.
- Teredo traffic hides native IPv6 addresses in IPv4 traffic, which complicates traffic monitoring and filtering.
Common Mitigations:
- Disable Teredo support on hosts and edge devices if not required for IPv6 transition.
- Filter or block UDP port 3544 on firewalls to prevent Teredo tunneling.
- Use deep packet inspection to identify and manage tunneled traffic.
- Favor native IPv6 deployment strategies to eliminate the need for transition technologies like Teredo.
Related Ports
the 8 most looked-up other ports in security — 216 ports carry that label.
| port | service | risk | |||
|---|---|---|---|---|---|
| :8881 | Atlasz Secure Server | TCP | Web Services | caution | 67.6k |
| :443 | HTTPS | TCPtls | Web Services | caution | 65.9k |
| :8291 | Winbox MikroTik Admin | TCP | Security | caution | 62.9k |
| :3268 | Microsoft Global Catalog (GC) | TCPUDP | Security | caution | 54.6k |
| :135 | Microsoft EPMAP | TCPUDP | Security | caution | 51.9k |
| :3128 | Squid Proxy HTTP | TCP | Web Services | caution | 45.8k |
| :8080 | HTTP Alternate | TCPtls | Web Services | caution | 44.9k |
| :7000 | Vuze HTTPS Tracker | TCPtls | Security | caution | 28.9k |
risk mix of the 8 listed
- caution100%
3 of 8 encrypted