3784

IANA registers TCP port 3784 as bfd-control (“BFD Control Protocol”). The supplied protocol specification, RFC 5881, describes BFD Control packets on UDP destination port 3784, not TCP. The evidence therefore does not establish what protocol, if any, runs over TCP 3784 or who should access it; its public internet exposure is Unknown.

RFC 5881 describes single-hop Bidirectional Forwarding Detection (BFD) as an operations and maintenance mechanism for checking connectivity between network systems, including routers and service endpoints. It says BFD is not suited to application-to-application failure detection across the Internet without a transport that provides TCP-friendly behavior.

For the documented single-hop protocol, BFD Control uses UDP 3784 and BFD Echo uses UDP 3785. The RFC also describes TTL or Hop Limit checks and recommends authentication for tunnel use. These details apply to the specified BFD traffic over UDP; they do not establish TCP behavior on port 3784.

TCP service

IANA registers bfd-control on TCP 3784; the supplied RFC specifies BFD Control over UDP, so TCP behavior is Unknown.

Exposure

Unknown. The evidence does not establish an intended audience or policy for TCP 3784.

Security context

RFC 5881 describes single-hop checks and TTL or Hop Limit protections for BFD Control; these are UDP protocol details, not evidence about TCP traffic.

IANA service name

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

TCP protocol use

Unknown; RFC 5881 specifies BFD Control over UDP destination port 3784 [Confirmed] — https://www.rfc-editor.org/rfc/rfc5881.txt

BFD purpose

Operations and maintenance connectivity checking between network systems [Confirmed] — https://www.rfc-editor.org/rfc/rfc5881.txt

TCP exposure policy

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