Port 1131CAC App Service Protocol (encrypted)

Encrypted CAC App Service Protocol traffic assigned to TCP and UDP port 1131.

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

also known as caspssl

Technical Details

what runs on :1131

CAC App Service Protocol (encrypted) is registered on port :1131 over tcp and udp to Enrique Corujo, assigned February 2006. We don't have a technical write-up for it beyond the IANA registry entry.

In nmap's internet-wide scan data this port is found open rarely. What's listening is often not the registered service, so check before you assume.

find what's listening on :1131

this machine

# linux
sudo ss -tulpn 'sport = :1131'

# macos / bsd
sudo lsof -nP -i :1131

# windows (then: tasklist /FI "PID eq <pid>")
netstat -ano | findstr :1131

another host

nmap -sV -p T:1131 <host>
sudo nmap -sU -sV -p U:1131 <host>

run it? the handshake, the implementations you meet in the wild and the flags that matter come from the engineers who do.

add technical details

Security Information

exposure of :1131

risk score

1/ 10safe

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

in transit

encrypted

payloads are protected on the wire

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

no security notes recorded for :1131 yet

known exploits, hardening advice, what a compromise looks like — suggest an edit if you know its exposure.

Record

iana registry entry

port: :1131
service: CAC App Service Protocol (encrypted)
transport: TCPUDP
encryption: tls / encrypted
assignment: iana registered
risk: 1/10safe
category: uncategorised
usage: Port 1131 is assigned to the CAC App Service Protocol in encrypted form. The assignment was registered by Enrique Corujo on 2006-02-01; public deployment details are not established.
lookups: 0rank 993
added: 2026-08-31
updated: 2026-08-31
references: IANA service name registry — port 1131

Something wrong?

This record is maintained by the engineers who use port 1131. 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 2026-08-31.

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

browse categories →

ports registered around :1131, by lookups.

port	service	proto	category	risk	views
:1080	SOCKS Proxy	TCPtls	Security	caution	16.1k
:1182	AcceleNet ITP	TCPUDP	Network Services	caution	12.4k
:1194	OpenVPN	TCPUDP	Security	caution	11.2k
:1110	EasyBits School Discovery	UDP	Network Services	caution	11.1k
:1169	Tripwire	TCPUDP	Security	caution	9.4k
:1167	Conference Call Signaling	UDP	Network Services	caution	9.1k
:1140	AutoNOC	TCPUDP	Network Services	caution	8.7k
:1109	Reserved Port 1109	UDP	Network Services	caution	7.9k

risk mix of the 8 listed

caution100%

1 of 8 encrypted

Port :1131CAC App Service Protocol (encrypted)

Technical Details

Security Information

Related Ports

Port 1131CAC App Service Protocol (encrypted)