3544

IANA registers TCP port 3544 as teredo (“Teredo Port”) and references RFC 4380. That assignment identifies a service name; it does not establish that Teredo runs over TCP or that any host uses this port. Whether TCP 3544 belongs on the public internet is Unknown from the supplied evidence.

RFC 4380 specifies Teredo as IPv6 tunneling over UDP for nodes behind IPv4 NATs. It identifies UDP 3544 as the port where Teredo servers wait for packets. The RFC notes that TCP tunneling was possible but would provide poor quality of service, and selects UDP instead. These protocol details describe UDP and do not establish TCP 3544 behavior.

The RFC discusses security risks of the Teredo service, including NAT mappings and relay misuse. Those concerns apply to the specified UDP-based design; the evidence does not show them in TCP traffic on port 3544. No deployment, prevalence, or malware observations were supplied.

Registered service

IANA lists teredo for TCP 3544 and references RFC 4380.

Protocol evidence

RFC 4380 specifies Teredo over UDP and names UDP 3544 as the server port; TCP use is Unknown.

Exposure

Unknown. The evidence does not establish the intended audience or deployment of TCP 3544.

IANA service name

teredo [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.csv

IANA description

Teredo Port [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.csv

IANA RFC reference

RFC 4380 [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.csv

Teredo transport specified

UDP [Confirmed] — https://www.rfc-editor.org/rfc/rfc4380.txt

Teredo server port

UDP 3544 [Confirmed] — https://www.rfc-editor.org/rfc/rfc4380.txt

TCP 3544 deployment or use

Unknown [Unknown] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.csv

Public internet exposure policy

Unknown [Unknown] — https://www.rfc-editor.org/rfc/rfc4380.txt