Port 2855Message Session Relay Protocol (MSRP)

MSRP carries instant messaging, file transfer, and other media sessions over TCP.

transport: tcp
in transit: cleartext
assignment: official
risk: 5/10
lookups: 0

also known as msrp

Technical Details

what runs on :2855

MSRP is a session-oriented, text-framed protocol defined by RFC 4975. After a TCP connection is established, peers exchange MSRP requests and responses containing transaction IDs, paths, headers, and message bodies; message chunks are terminated with MSRP boundary markers. SIP/SDP commonly negotiates the MSRP session and endpoint paths, while RFC 4976 defines MSRP relays. TCP 2855 is the standard cleartext port; TLS-protected MSRP is commonly identified as msrps and uses a separate service/port.

Security Information

exposure of :2855

risk score

5/ 10caution

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

file transfer averages 3.8 across 148 ports — this one sits 1.3 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

every listening transport is another surface to filter at the edge

security overview

MSRP is not encrypted by default on TCP 2855, so messages and transferred files can be observed or modified in transit. An exposed endpoint may disclose sensitive communications, accept unwanted sessions, or be abused as a relay; restrict it to trusted signaling peers or relay networks and use authenticated TLS where supported.

Record

iana registry entry

port: :2855
service: Message Session Relay Protocol (MSRP)
transport: TCP
encryption: cleartext
assignment: iana registered
risk: 5/10caution
category: File Transfer Voice and Chat
usage: This port carries Message Session Relay Protocol sessions, commonly negotiated through SIP and SDP for instant messaging, file transfer, and conferencing. MSRP endpoints and relays may listen on TCP 2855; internet exposure is uncommon.
lookups: 0rank 994
added: 2026-09-03
updated: 2026-09-03
references: IANA service name registry — port 2855
RFC 4976

Something wrong?

This record is maintained by the engineers who use port 2855. 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 2026-09-03.

01edit any field on a page of its own
02a model checks it for accuracy and spam
03clean and confident goes live immediately

edit this record →back to the registry

Related Ports

all 148 in file transfer →

the 8 most looked-up other ports in file transfer — 148 ports carry that label.

port	service	proto	category	risk	views
:9080	Groove RPC	TCPUDP	Web Services	caution	70.8k
:17500	Dropbox LAN Sync	TCPUDP	File Transfer	caution	43.7k
:548	Apple Filing Protocol	TCP	File Transfer	caution	36.8k
:7000	Vuze HTTPS Tracker	TCPtls	Security	caution	28.9k
:1337	PowerFolder P2P	TCP	Security	caution	27.1k
:9001	SharePoint Authoring		Web Services	caution	26.3k
:8080	FilePhile Relay	UDP	File Transfer	caution	25.6k
:1337	WASTE Encrypted Sharing	TCP	Security	caution	22.9k

risk mix of the 8 listed

caution100%

1 of 8 encrypted

Port :2855Message Session Relay Protocol (MSRP)

Technical Details

Security Information

Related Ports

Port 2855Message Session Relay Protocol (MSRP)