Port 9899SCTP over UDP (RFC 6951)

UDP port 9899 carries SCTP packets encapsulated in UDP, commonly to traverse networks that block native SCTP.

transport: udp
in transit: cleartext
assignment: official
risk: 2/10
lookups: 0

also known as sctp-tunneling, SCTP/UDP

Technical Details

what runs on :9899

RFC 6951 encapsulates SCTP packets in UDP datagrams, using UDP port 9899 as the default destination port. The SCTP association itself still uses SCTP's INIT, INIT-ACK, COOKIE-ECHO, and COOKIE-ACK handshake and SCTP packet framing; the UDP layer carries those packets between endpoints. This is an encapsulation mechanism, not encryption: SCTP's CRC32c checksum detects corruption but does not provide confidentiality or cryptographic authentication. The inner SCTP application determines what data or service is available.

Security Information

exposure of :9899

risk score

2/ 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 1,859 ports — this one sits 0.6 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

udp

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

security overview

UDP encapsulation does not encrypt or authenticate the SCTP traffic, and it does not make an exposed inner SCTP service safe. An internet-reachable listener may be probed or used to reach the SCTP application behind it; restrict access to expected peers and assess the inner service's security. The port is uncommon in scan data, so an unexpected listener warrants investigation.

Record

iana registry entry

port: :9899
service: SCTP over UDP (RFC 6951)
transport: UDP
encryption: cleartext
assignment: iana registered
risk: 2/10safe
category: Network Services
usage: This is the IANA-assigned default UDP port for SCTP encapsulation defined by RFC 6951. Engineers may encounter it where SCTP needs to cross NATs or firewalls that do not pass native SCTP; it is not a general-purpose tunnel for arbitrary traffic.
lookups: 0rank 993
added: 2026-10-16
updated: 2026-10-16
references: IANA service name registry — port 9899
RFC 6951

Something wrong?

This record is maintained by the engineers who use port 9899. 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 2026-10-16.

01edit any field on a page of its own
02a model checks it for accuracy and spam
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edit this record →back to the registry

Related Ports

all 1,859 in network services →

the 8 most looked-up other ports in network services — 1,859 ports carry that label.

port	service	proto	category	risk	views
:9080	Groove RPC	TCPUDP	Web Services	caution	70.8k
:6543	Jetnet	UDP	Network Services	caution	65.3k
:5938	TeamViewer	TCPUDP	Remote Access	caution	65.0k
:8291	Winbox MikroTik Admin	TCP	Security	caution	62.9k
:3233	WhiskerControl Protocol	TCPUDP	Network Services	caution	61.9k
:3268	Microsoft Global Catalog (GC)	TCPUDP	Security	caution	54.6k
:135	Microsoft EPMAP	TCPUDP	Security	caution	51.9k
:3128	Tatsoft Default HTTP Proxy	TCP	Web Services	caution	46.8k

risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :9899SCTP over UDP (RFC 6951)

Technical Details

Security Information

Related Ports

Port 9899SCTP over UDP (RFC 6951)