Port 2101RTCM SC-104

Carries RTCM differential-GNSS correction messages between receivers, base stations, and NTRIP casters.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 4/10
lookups: 0

also known as RTCM 104, NTRIP correction stream

Technical Details

what runs on :2101

RTCM SC-104 primarily defines the binary framing and message formats for GNSS correction data rather than a universal session handshake. Modern RTCM 3 messages use a 0xD3 preamble, a length field, message payload, and CRC-24Q; older RTCM revisions use different framing. TCP is common for continuous NTRIP streams on port 2101, where an HTTP-like request and caster response may precede the RTCM data; UDP deployments generally send datagrams containing RTCM frames without that exchange.

Security Information

exposure of :2101

risk score

4/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

network services averages 3.7 across 658 ports — this one sits 0.3 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

tcp · udp

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

security overview

RTCM streams are normally unencrypted, and NTRIP authentication is deployment-dependent. Internet exposure can disclose receiver or station metadata and allow unauthorized consumption or injection of correction data, potentially degrading positioning accuracy; expose the service only to intended GNSS clients and protect it with access controls or a secure tunnel.

Record

iana registry entry

port: :2101
service: RTCM SC-104
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 4/10caution
category: Network Services IoT
usage: RTCM SC-104 is used to transport differential-GNSS correction data from a reference station or NTRIP caster to rover receivers. TCP port 2101 is especially associated with NTRIP correction streams, while some equipment also sends RTCM data over UDP.
lookups: 0rank 994
added: 2026-08-22
updated: 2026-08-22
references: IANA service name registry — port 2101

Something wrong?

This record is maintained by the engineers who use port 2101. 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 2026-08-22.

01edit any field on a page of its own
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edit this record →back to the registry

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all 658 in network services →

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risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :2101RTCM SC-104

Technical Details

Security Information

Related Ports

Port 2101RTCM SC-104