Port 1988Cisco RSRB Priority 2

Port for Cisco Remote Source-Route Bridging (RSRB) priority 2 traffic.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 6/10
lookups: 0

also known as tr-rsrb-p2, Cisco RSRB P2

Technical Details

what runs on :1988

RSRB is a Cisco-specific encapsulation protocol for carrying Token Ring LAN frames between bridge peers. IANA lists this priority-specific service on both TCP and UDP; Cisco RSRB deployments use the related RSRB port range, including separate priority channels, rather than a general-purpose application protocol. Traffic is legacy bridging traffic and is not encrypted by the protocol itself; the Priority 2 designation identifies a forwarding queue or channel within the RSRB arrangement.

Security Information

exposure of :1988

risk score

6/ 10risk

treat as sensitive. widely scanned and regularly exploited when reachable — restrict it to known sources.

network services averages 2.6 across 1,683 ports — this one sits 3.4 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

RSRB should not be exposed to the public Internet. An exposed endpoint may allow probing, denial of service, or injection and forwarding of bridged Token Ring traffic, depending on the Cisco configuration; captured traffic is also cleartext. Restrict it to trusted peer addresses and use a protected tunnel or other network-layer controls when legacy RSRB must cross an untrusted network.

Record

iana registry entry

port: :1988
service: Cisco RSRB Priority 2
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 6/10risk
category: Network Services
usage: This port is used by Cisco IOS Remote Source-Route Bridging (RSRB) to transport Token Ring source-routed frames between remote bridge peers. It is normally encountered only on legacy Cisco networks connecting Token Ring segments across an IP network.
lookups: 0rank 993
added: 2026-08-29
updated: 2026-09-22
references: IANA service name registry — port 1988

Something wrong?

This record is maintained by the engineers who use port 1988. 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 2026-09-22.

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 1,683 in network services →

the 8 most looked-up other ports in network services — 1,683 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 :1988Cisco RSRB Priority 2

Technical Details

Security Information

Related Ports

Port 1988Cisco RSRB Priority 2