Port 13821DSM-CC Download Protocol

DSM-CC download signaling for delivering data or software modules to digital-TV receivers and other clients.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 1/10
lookups: 0

Technical Details

what runs on :13821

IANA assigns port 13821 over both TCP and UDP to the DSM-CC Download Protocol. In the MPEG-2 DSM-CC standard, download signaling describes modules and their blocks, which clients can request and assemble; messages include DownloadInfoIndication and DownloadDataBlock. Broadcast systems commonly encapsulate these messages in MPEG transport-stream sections, so an IP listener on this port is deployment-specific rather than a universal feature of DSM-CC. The port number alone does not establish a particular TCP handshake, UDP framing, or related-port scheme.

Security Information

exposure of :13821

risk score

1/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

network services averages 2.6 across 1,898 ports — this one sits 1.6 below.

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

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

DSM-CC download traffic is not encrypted by default simply because it uses this port; deployments should not assume confidentiality or peer authentication without a separate protective layer. Because the protocol can deliver data or software modules, restrict any IP listener to trusted receivers and networks, and avoid exposing it to the public internet. The assignment is obscure and has not been observed open in the cited internet-wide scan data.

Record

iana registry entry

port: :13821
service: DSM-CC Download Protocol
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 1/10safe
category: Network Services Media
usage: The assignment is for the MPEG DSM-CC Download Protocol, used in digital-TV systems to deliver data or software modules to receivers. Broadcast deployments commonly carry DSM-CC in MPEG transport streams rather than expose this port as an IP service.
lookups: 0rank 993
added: 2026-10-17
updated: 2026-10-17
references: IANA service name registry — port 13821

Something wrong?

This record is maintained by the engineers who use port 13821. Every field on it is editable — change what's wrong, say how you know, and a reviewer publishes it, usually within a minute. Last touched 2026-10-17.

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risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :13821DSM-CC Download Protocol

Technical Details

Security Information

Related Ports

Port 13821DSM-CC Download Protocol