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// Directory & authentication

Port 2711: SSO Control

Port 2711 is assigned by IANA to sso-control (SSO Control).

2711

How sso-control works

Directory & authentication
userdirectorysso-controlresponse userdirectorysso-controlresponse

The client proves who it is on port 2711 and gets an answer (or a ticket) it can use with other services.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Directory & authentication
01 Security

Is port 2711 dangerous?

We have no specific security note for port 2711. Its risk depends on the program actually listening on it. General advice for directory & authentication services:

  • Keep directory and authentication services on internal networks.
  • Require signing or TLS and disable anonymous queries.
  • Monitor authentication failures for spraying and brute force.
02 Registry

IANA registry entries for port 2711

ServicePortTransportDescriptionReferenceUpdated
sso-control 2711 TCP, UDP SSO Control - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 2711, and is it reachable?

Linux

sudo ss -ltnup 'sport = :2711'      # process listening on 2711
sudo lsof -nP -i :2711

macOS

sudo lsof -nP -i :2711

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 2711 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 2711
netstat -ano | findstr :2711

From another machine

nmap -p 2711 -sV <host>
sudo nmap -sU -p 2711 <host>
nc -zv <host> 2711

Block it in the firewall

sudo ufw deny 2711/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 2711" -Direction Inbound -LocalPort 2711 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 2711 used for?

Port 2711 is assigned by IANA to sso-control (SSO Control).

Is port 2711 TCP or UDP?

Port 2711 is registered for TCP and UDP.

Is it safe to open port 2711?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Keep directory and authentication services on internal networks.

How do I check if port 2711 is open?

On Linux run "ss -ltnup 'sport = :2711'", on macOS "lsof -nP -i :2711", and on Windows "netstat -ano | findstr :2711" to see the local process. From another machine, "nmap -p 2711 <host>" shows whether it is reachable.

05 Related
:389 LDAP tcp · udp · high risk :636 LDAPS tcp · udp · moderate risk :88 Kerberos tcp · udp · high risk :3268 Global Catalog (LDAP) tcp · udp · high risk :1812 RADIUS udp · tcp · moderate risk :31 MSG Authentication tcp · udp :49 Login Host Protocol (TACACS) tcp · udp :56 XNS Authentication tcp · udp

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